Performance of a Battery-Powered Self-Propelled Coriander Harvester

Abstract

Coriander is a significant crop, playing an essential role in daily life for various purposes, including flavouring curries and medicinal uses, among others. Despite its importance, coriander is still harvested manually. To address this, developed a self-propelled battery-operated coriander harvester, designed with ergonomics, environmental sustainability and affordability for small and marginal farmers in mind. The harvester is equipped with a main frame, a lead-acid battery, a BLDC motor, a reciprocating cutter bar, a PU conveyor belt, a collection bag, a handle, and transport wheels. The harvester was tested on the coriander crop, and the results were analyzed using Design Expert software to optimize various operational parameters. The harvester’s performance was evaluated at three forward speeds: 1.5 km/h, 2 km/h, and 2.5 km/h, resulting in covered areas of 0.114 ha, 0.164 ha, and 0.22 ha, with field efficiency values of 76%, 82%, and 88%, respectively. Optimal harvesting conditions were identified by design expert software at a forward speed of 1.64 km/h, with a conveyor driving pulley at level 3 (50.8 mm) and a cutting height at level 2 (75 mm). Under these conditions, the harvester achieved a harvesting efficiency of 97.24% and a cutting efficiency of 98.2%, with minimal conveying loss of 0.96%. The theoretical field capacity was 0.16 ha/h, the actual field capacity was 0.131 ha/h, and the overall field efficiency was 81.8%.

1. Introduction

Leafy vegetables are recognised for their nutritional importance, medicinal properties, and cultural significance, making them integral to the traditional diets and cultural practices of many societies [1,2,3]. They are an important element of meals, providing critical vitamins A, B, and C, as well as minerals such as iron and calcium, and key bioactive compounds [4]. Increased understanding of the health benefits of leafy green vegetables in developing nations is currently driving up demand and consumption [4]. Coriander, like other green vegetables, is rich in vitamins C, A (β-carotene), B1, B2, protein, fat, minerals, fiber, carbohydrates, water, calcium, phosphorus, iron, carotene, thiamine, riboflavin, sodium, potassium, and oxalic acid [5]. In addition to fatty and essential oils, coriander seeds contain 21.5% carbs, 32.5% fiber, 14% protein, 11.1% moisture, and 4.3% minerals [6]. Coriander has a long history as a traditional medicine [7] and aromatic plant in the Apiaceae family [8]. The leaves have historically been used for their herbal properties when added to meals [9], as a flavouring element [10], and have been demonstrated to stimulate urine output and discharge while decreasing fever [11]. In the Indian subcontinent, they are often used in boiling products and soups and are added at the end of cooking [12,13].

Climate change has a significant impact on agricultural yields [14]. It is primarily caused by pollutants produced by internal combustion engines, which are widely used in agricultural machinery [15] and account for approximately 95% of the energy consumed for propulsion [16]. Agriculture and land-use change account for approximately one-quarter of total global greenhouse gas emissions [17]. The Paris Agreement established global warming objectives of 2 °C and 1.5 °C by 2100, which have been supported academically by recently published IPCC assessments [14]. Environmental issues arising from agricultural activities are becoming increasingly important worldwide as ecological sustainability is prioritised [18,19]. The global emphasis on reducing greenhouse gas (GHG) emissions has led to increased interest in climate-smart agricultural approaches, such as regenerative, digital, and regulated atmosphere farming systems [20]. Electrification can help make automobiles more efficient and create new opportunities for work optimisation [21]. Electric vehicle adoption is mainly driven by environmental concerns and government initiatives [22]. As agricultural machinery is critical to achieving an adequate supply of food for a growing population, changes in common agricultural engineering thinking are required for the development of new farm equipment that can outperform conventional ones in terms of environmental harm, performance, productivity and safety [23].

Agriculture is one of the major occupations in India and a significant contributor to the country’s economy [24]. The rising cost and declining availability of manual labour [25] have accelerated automation in nearly all processes of modern agriculture, except for the harvesting of leafy vegetables. Traditional harvesting is a labor-intensive and expensive procedure; farmers often spend 25 to 30 percent of crop production costs on harvesting [26]. At present, in India, this crop is harvested manually with a sickle in the majority of smallholding farms [27]. During harvesting, 77% of participants experienced discomfort in the lower back, shoulders, neck, hands, wrists, and fingers, with age being the primary cause of pain in all body locations except the neck and shoulders [28]. Mechanisation in agriculture now encompasses the majority of farming activities, aiming to eliminate physically demanding work, enhance job scheduling, and increase production [29]. Agriculture has evolved from a labour-intensive operation to one that is heavily mechanised over the last decade. Numerous technological developments, including harvesting equipment, sensors, and drones, have been combined to improve information collection and transmission, enhancing harvest efficiency and allowing for more precise and rapid decision-making [30]. Automation in agriculture is necessary for producing food, fiber, and fuel to a rapidly rising population, especially since harvesting is an essential component in farming [31]. Taking the above debate into account, a self-propelled battery-powered coriander harvester was developed that has been ergonomically built to benefit growers. This harvester aims to reduce human labour, eliminate post-harvest losses, increase production, mitigate risks associated with adverse weather conditions, lower total harvesting expenses, and facilitate early crop sales. In this study, the performance of the designed coriander harvester is analysed with an emphasis on harvesting efficiency, crop loss, and possible economic effects on coriander farming. The design of the coriander harvester is based on the study of various existing types of electrified harvesters. Okafor (2013) [32] designed and built a self-propelled lawn mower powered by a battery-powered DC motor, using pulleys for blade operation and speed management, a 12 V alternator in the charging unit, and a lift mechanism for adjusting cut height, achieving an 89.55% cutting efficiency with 0.24 kN of human effort during evaluation. Amrutesh et al. (2014) [33] developed a solar-powered lawn cutter featuring a scotch yoke mechanism, which included a 50 W solar panel (12 V), a 12 V battery (7.2 Ah), a solar charger, a circuit breaker, and blades. Kiran et al. (2017) [34] shaped a battery-powered reaper for harvesting rice and wheat in Bangladesh, with a 1100 W, 48 V BLDC motor with 450 rpm to drive the cutting mechanism and traction wheels, powered by four 12 V batteries, a cutting width of 0.6 m, an average field capacity of 0.13 ha/h at 2.17 km/h, and a cutting efficiency of 98.24%. Mathan et al. (2019) [35] developed a power weeder into an electrically driven system by replacing the 5.5 hp gasoline engine with a 2 hp, 1500 W DC motor powered by batteries, therefore reducing pollution.

2. Materials and Methods

While offering a description of the necessary stages, it is essential to note that building such a coriander harvester takes engineering abilities as well as mechanical and electrical knowledge. We designed the harvester’s mechanical construction, which includes the cutting mechanism (Diamond, India brand), BLDC motor (CY, Qingdao, China), batteries (Exide, Kolkata, India), MCB (Legrand, Limoges, France), controller (CY, Qingdao, China), conveyor system (Kyungin, Incheon, Republic of Korea), and wheels. We used lightweight and sturdy materials to keep the weight under control and ensure optimal harvesting. Two pneumatic wheels were mounted on the back edges of the frame’s two corners. Two caster wheels with sliding adjustment were installed on the front side of the frame to adjust the cutting height and provide support. The BLDC motor was positioned three-quarters of its length from the front end of the frame and one-quarter of the length from the right side of the body. The controller, connection box, and battery stand were positioned between the rear wheels. The MCB was linked to the frame by a 50.8 mm bright bar, 150 mm in length, which was adjusted using a nut and bolt on the right side of the motor. The battery stands measured 560 mm in length, 76.2 mm in height, and 190 mm in breadth, and it was mounted on the back side of the frame, between the rear wheels. The controller was attached to a 300 mm long, one-inch light bar using a nut and bolt adjustment on the motor’s backside. The junction box was also fixed, along with the controller. A voltage display was inserted between the handles. The shaft linked to the motor was insufficiently sized; thus, a 13-tooth sprocket was welded to the BLDC motor shaft using a 24 mm inner diameter tubing. The primary shaft was mounted on pedestal bearings 500 mm from the front end of the frame. This primary shaft receives power from the BLDC motor via a 50-tooth sprocket connected by a 69-link chain; thus, the sprocket rotates four times less than the BLDC motor shaft. The main shaft was equipped with two pulleys, a connecting rod, and a small sprocket secured by grab screws to convey power to all harvester elements. An angle bar measuring 1050 mm was welded to the front portion of the structure to connect to the cutter unit, which receives power from the connecting rod. The reel was linked to the frame at the front end at a 135° angle. For conveyor belt support, two square pipes, each 1500 mm in length, were welded at the frame’s two front corners at an angle of 18°. Two square pipes, up to 457 mm in diameter, were welded to the conveyor belt to hold the pipes in place and secure the collecting bag. A 38 mm circular pipe was utilised to connect the collecting bag’s support pipes. According to the operator, the handle was fastened to the circular pipe using a flexible connection that allowed for height modification. We considered ergonomics while designing the harvester to make it more user-friendly and easier to operate. We assembled all of the components according to the design, ensuring that all connections and interfaces function properly. It works by automating the cutting and collection of crops, reducing the requirement for manual labour and expediting the harvesting procedure. The harvester was powered by a portable battery pack, eliminating the need for additional power or fuel. The battery gives electricity to the harvester’s motor and other electrical components. First, switch the ignition starting to the right before activating the MCB. After turning on the ignition starter, the display screen displays the voltage level. Once the ignition starter is turned on, all of the harvester’s components, including the cutting unit, backside wheels, conveyor unit, reel unit, and other elements, are activated by the action of the throttle. Figure 1a shows the internal view of the harvester, while Figure 1b presents the designed prototype view.

2.1. Theoretical Power Calculation for the Working of Self-Propelled Battery-Operated Leafy Vegetable Harvester

The power requirement of the developed harvester plays the most crucial role in its viability. The most important consideration was the human average walking speed, which is approximately 0.7–0.8 m/s, as specified in the design of the harvester [36]. The self-propelled, battery-operated leafy vegetable harvester comprises four key functional units: the cutting blade unit, reel unit, conveyor system, and power train, including the back wheels. The power source for these components is batteries. Therefore, there is a need for individual power calculations for each functional unit, which are clearly explained in

Table 1. Parameters considered for the power requirement of the harvester.

Unit/Component	Parameter	Value	Power Requirement
Cutter bar	Specific power requirement	0.513 hp/m	383 W
Speed	Avg walking speed	0.7 m/s
Reel	Diameter	0.3 m
	Reel index	1.25–1.50
	Reel speed, (1.5× avg walking speed)	1.05 m/s
	Weight	10 kg = 98 N
	Calculated rotational speed	67 rpm from Equation (1)
	Torque	14.7 Nm from Equation (2)
	Power	–	103 W from Equation (3)
Conveyor system	Leaf load (a)	10 kg/m
	Travel distance of material (b)	1.5 m
	Total mass of yield over the conveyor (A = a × b)	15 kg
	Total mass of rollers (driver and driven roller) (c)	10 kg
	Mass of conveyor belt with cleats, (d)	5.5 kg
	Mass of pulley, (e)	0.2 kg
	Self-mass of conveyor, (B = c + d + e)	15.7 kg
	Total mass handled, (A + B)	30.7 kg
	Peripheral speed (1.25× avg. walking speed)	0.875 m/s
	Power	–	261 W from Equation (4)
Rear wheel power train	Machine weight	100 kg
	Coefficient of rolling resistance	0.2 from Equation (5)
	Force	196.2 N from Equation (6)
	Wheel radius	0.19 m
	Torque	37.27 Nm from Equation (2)
	Revolutions	35 rpm
	Power	–	117 W from Equation (7)
Total power	Theoretical requirement	–	864 W

and following sections for the total power requirement of the harvester.

• Power for the cutter unit

The power required for cutting a crop with a cutter bar can be estimated at 0.513 hp per meter of cutter length [37].

So, the required power for the cutter bar was 0.513 hp = 383 W.

• Power for the reel unit

The velocity of the reel should be higher than the machine’s forward speed [38].

$$\mathrm{The}\mathrm{rotational}\mathrm{speed}\mathrm{of}\mathrm{the}\mathrm{reel}\mathrm{is}\mathrm{calculated}\mathrm{as}\mathrm{N}=\frac{60 v }{\pi d},$$

(1)

where

N = Rotational speed, rpm;

V = Velocity, m/s;

D = Diameter, m.

Torque, (N − m) = F × R,

(2)

where

F = Force, N;

R = Radius of reel, m.

$$\mathrm{Power},\mathrm{W}=\frac{2\pi NT}{60},$$

(3)

• Power for conveyor system

The velocity of the conveyor should be higher than the harvester speed to avoid clogging of cut leaves. The calculation was based on the total mass to be lifted by the conveyor and the self-mass of the system involved in the conveyor’s transmission system.

• Total mass of the yield to lifted

In the case of the conveyor, the material was lifted at a 20-degree angle horizontally. It was considered that the leaves’ mass might reach the conveyor.

• Self-mass of the conveyor to be lifted

Now, the peripheral speed of the conveyor was taken as 1.25 times the harvester’s average running speed.

$$\mathrm{P}=\frac{M\times S}{75},$$

(4)

where

P = Power required, hp;

M = Power required, kg;

S = Peripheral speed, m/s.

• Power for power train of the back wheels

Let the requirement of the number of revolutions of the wheel per minute for an average walking speed = 35 rpm.

$$\mathrm{Coefficient}\mathrm{of}\mathrm{rolling}\mathrm{resistance}=\frac{force}{vertical load},$$

(5)

Force = Coefficient of rolling resistance × Weight of machine, (kg),

(6)

$$\mathrm{P}=\frac{2\pi NT}{60},$$

(7)

where

P = Power, W;

N = Number of revolutions, rpm;

T = Torque, N-m.

• Total power requirement

From Table 1, the total theoretical power requirement to run the harvester is 864 W. Thus, a 900-watt BLDC motor was easily available in the market. So, it was selected as the power source of the harvester.

2.2. Description of the Experimental Area

The study used a preset experimental setup. Each experiment was run for each possible combination of factors (

Table 2. Plan of the experiment of the harvester in the field.

S. No	Independent Variable		Dependent Variables
1	Crop	Coriander	Effective field capacity, (ha/h) Theoretical field capacity, (ha/h) Field efficiency, (%) Cutting efficiency, (%) Conveying loss, (%) Harvesting efficiency, (%)
2	Machine level (3)	Conveyor driving pulley; M1 = 50.8 mm pulley, M2 = 76.2 mm pulley, M3 = 101.6 mm pulley.
3	Forward Speed (3)	1.5 km/h, 2 km/h, 2.5 km/h
4	Cutting height (2)	50 mm, 75 mm

). The experiment included selected combinations of independent variables, each of which had three replications. Three levels of forward speed—1.5 km/h, 2 km/h and 2.5 km/h—were chosen based on statistical design. These speeds were achieved by varying the conveyor drive pulley sizes to 50.8 mm, 76.2 mm, and 101.6 mm, as well as the cutting heights to 50 mm and 75 mm for the selected crops. After each experiment, characteristics such as cutting efficiency, conveyance loss and harvesting efficiency, were measured.

2.3. Experimental Design

The experimental setup shown in Figure 2 used a factorial randomised block design of trials. The experimental data for all dependent factors were statistically analysed using the Design-Expert software v23.1.

Based on the selected parameters, subsequent treatment combinations were taken.

The total quantity of possible treatment combinations in the field is 3 × 3 × 2 = 18.

Number of repetitions = 3.

So, the total quantity of events is 18 × 3 = 54.

Net plot dimensions: 54 × 3 = 162 m².

Overall dimensions of all the plots = 162 m².

The crop was cultivated on the farm using specified agronomical procedures. The sum of all areas of the coriander crop seeded was 180 m², including all boundaries.

2.4. Physical Properties of Soil

To investigate the soil’s physical characteristics, soil samples were collected consistently from various locations across the field. Prior to harvesting, the soil parameters, including bulk density [39] (Kushwaha et al., 2015), moisture content [40], and cone index, were assessed in the field at various soil depths.

2.5. Field Evaluation of Self-Propelled Battery-Operated Coriander Harvester

The performance of the self-propelled battery-powered coriander harvester was tested in the field using essential measures such as adequate field capacity, theoretical field capacity [41], field efficiency [41] and cutting efficiency (2017) [34]. Furthermore, conveyance loss (%) and harvesting efficiency (%) were used to evaluate overall performance. All trials were conducted according to the experimental plan to ensure uniform data collection and analysis.

3. Results and Discussion

3.1. Field Condition Before Harvesting

The efficacy of the developed coriander harvester is governed not only by its design and characteristics, but also by the field conditions in which it operates. As a result, ten randomly selected places were identified in the coriander-growing field. The mean soil moisture content and average soil bulk density were found to be 20.01% (on a dry basis) and 1.19 g/cc, respectively. The average cone index value was 12.9 kg/cm² at a depth of 150 mm.

3.2. Crop Parameters Before Harvesting

The coriander crop’s characteristics were measured at the harvesting stage. These factors included a range of variables, including plant height, stem diameter, stem moisture content, and bed spacing. The coriander plant exhibited a moisture content range of 19–26% (fresh weight basis), with leaves containing 82–88% moisture and stems 14–20%. The stem diameter was observed in the range of 3.0 ± 0.5 mm.

Table 3. Average observation of the crop parameters.

First time Harvesting
Crop Parameters	Particular
Avg. plant height, (cm)	31.88
Avg. stem diameter, (mm)	3.15
Avg. row to row spacing, (cm)	15
Avg. distance between beds, (cm)	30
Second Time Harvesting
Crop Parameters	Particular
Avg. plant height, (cm)	32.84
Avg. stem diameter, (mm)	3.30
Avg. row-to-row spacing, (cm)	15
Avg. distance between beds, (cm)	31
Third Time Harvesting
Crop Parameters	Particular
Avg. plant height, (cm)	30.50
Avg. stem diameter, (mm)	3.50
Avg. row-to-row spacing (cm)	15
Avg. distance between beds, (cm)	32

provides specific statistics, as well as a comprehensive overview of the average values for these characteristics.

3.3. Evaluation of Machine Variables for Coriander Crop

Field experiments were conducted to study the various machine variables and their effect on the selection of optimum machine parameters. The studies were conducted at different levels of the forward speeds (1.5 km/h, 2 km/h and 2.5 km/h), conveyor driving pulleys (level 1 of A (101.6 mm), level 2 of A (76.2 mm), level 3 of A (50.8 mm)) and cutting heights (level 1 of B (50 mm), level 2 of B (75 mm)). Figure 3 illustrates the field performance of the developed self-propelled battery-operated coriander harvester, while Figure 4a displays the features of the post-harvest plants and the measurement of the cutting height in Figure 4b.

Using a response surface study design—a type of randomised design—the analysis was conducted with the aid of Design-Expert software. The I-optimal coordinate exchange design type was employed, and a two-level factorial (2FI) design model was applied. The purpose of this approach was to systematically investigate and understand the relationships between the selected independent variables and dependent variables. The experimental design consisted of three forward speeds, two cutting heights, and three different conveyor driving pulley sizes, each of which was repeated three times. This combination produced 20 experimental runs. This approach aimed to thoroughly examine the effects of these independent input factors on the harvesting efficiency, conveying loss and cutting efficiency dependent variables.

3.3.1. Cutting Efficiency

The cutting efficiency percentages for different forward speeds, different sizes of conveyor driving pulleys and different levels of cutting height are shown in Figure 5 and Figure 6. The average of the observations for cutting efficiency at each treatment are included in

Table 4. Average of cutting efficiency (%) at different levels of variables in coriander.

S. No	Forward Speed (km/h)	Conveyor Driving PULLEY Size, (mm)	Cutting Efficiency, (%)
			Cutting Height (mm)
			50	75
1	1.5	101.6	97.49	97.6
2		76.2	97.50	97.7
3		50.8	97.53	97.72
4	2	101.6	98.04	98.15
5		76.2	98.09	98.25
6		50.8	98.11	98.36
7	2.5	101.6	98.69	98.78
8		76.2	98.72	98.8
9		50.8	98.8	98.9

.

The cutting efficiency for coriander with developed harvester had a mean value of 97.91% with a standard deviation of 0.0689 and a coefficient of variation of 0.0703%. The corrected R² of 0.9832 and the expected R² of 0.9537 agreed rather well, with the difference being less than 0.2. The signal-to-noise ratio is measured with enough precision. A ratio higher than 4 was preferred. An adequate signal is indicated by a ratio of 28.935. The design space may be navigated using this approach (

Table 5. Influence of design variables on cutting efficiency in coriander for an experimentally developed harvester (ANOVA).

Source	Sum of Squares	DF	Mean Square	F-Value	p-Value
Model	5.31	10	0.5305	111.91	<0.0001	Significant
A-Forward speed, (km/h)	5.11	1	5.11	1077.08	<0.0001
B-Conveyor driving pulley size, (mm)	0.0416	2	0.0208	4.39	0.0467
C-Cutting height, (mm)	6.703 × 10−9	1	6.703 × 10−9	1.414 × 10−6	0.9991
AB	0.0008	2	0.0004	0.0889	0.9157
AC	0.0005	1	0.0005	0.1029	0.7557
BC	0.0004	2	0.0002	0.0426	0.9584
A2	0.0219	1	0.0219	4.62	0.0601
Residual	0.0427	9	0.0047
Lack of fit	0.0191	4	0.0048	1.02	0.4786	Not significant
Pure Error	0.0235	5	0.0047
Cor Total	5.35	19
Std. Dev.		0.0689	R2		0.9920
Mean		97.91	Adjusted R2		0.9832
C.V. %		0.0703	Predicted R2		0.9537
			Adequate precision		28.9351

). The model F-value of 111.91 indicates that the model is significant. An F-value of this magnitude was just 0.01% likely to be the result of noise. Model terms were significant when the p-value was less than 0.0500. Here, significant terms for the model were A and B. Values higher than 0.1000 signify lack of significance for the model terms. The lack of fit F-value of 1.02 implies that the lack of fit was not significant. There was a 47.86% chance that a lack of fit F-value this large could occur due to noise. Non-significant lack of fit was adequate, making the model fit.

The final equations, in terms of actual factors for cutting efficiency (%), are in the following conditions:

➢

Conveyor driving pulley size, (101.6 mm):

Cutting height, (50 mm) = 96.6254 − 0.152939 A + 0.368112 A²,

(8)

Cutting height, (75 mm) = 96.5744 − 0.121856 A + 0.368112 A².

(9)

➢

Conveyor driving pulley size, (76.2 mm):

Cutting height, (50 mm) = 96.7161 − 0.162808 A + 0.368112 A²,

(10)

Cutting height, (75 mm) = 96.643 − 0.131724 A + 0.368112 A².

(11)

➢

Conveyor driving pulley size, (50.8 mm):

Cutting height, (50 mm) = 96.6727 − 0.114745 A + 0.368112 A²,

(12)

Cutting height, (75 mm) = 96.6102 − 0.0836617 A + 0.368112 A².

(13)

This equation should not have been employed to calculate the relative influence of each element since the coefficients have been adjusted to suit the units of each factor, and the intercept was not in the center of the design space.

Effect of the Individual Variable on Cutting Efficiency in Coriander

From Figure 5a, evaluate the impact of forward speed on coriander cutting efficiency. The cutting efficiency exhibits a minimum value of 97.28% at the lowest forward speed of 1.5 km/h while reaching its pinnacle at 98.62% with the forward speed of 2.5 km/h. Similar results were observed, where cutting efficiency increased along with the forward speed of the harvester, according to the study conducted by [42] (Younis et al. 2012).

Examine Figure 5b to see how the size of the conveyor driving pulley affects coriander harvesting efficiency. Notably, with a conveyor driving pulley size of 50.8 mm, the cutting efficiency was measured as 97.9%, with a minor increase to 97.96% when a 101.6 mm pulley was used. This analysis reveals that the size of the conveyor driving pulley has no significant effect on coriander cutting efficiency.

In Figure 5c, examine the relationship between cutting height and coriander cutting efficiency. Cutting efficiency was recorded at 97.8% at a cutting height of 50 mm, which increased slightly to 97.9% when the cutting height was increased to 75 mm. According to Atallah’s (2014) [43] study, differences in cutting height resulted in a comparable improvement in cutting efficiency. This investigation suggests that cutting height has a minor effect on coriander cutting efficiency. The higher cutting height enhances the harvester’s ground clearance, enabling better field movement and resulting in increased cutting efficiency.

Effect of the Combination of Variables on Cutting Efficiency in Coriander

Effect of Forward Speed and Selection of Conveyor Driving Pulley on Cutting Efficiency of Coriander.

In Figure 6a, explore the relationship between forward speed, conveyor driving pulley size on coriander cutting efficiency. At a forward speed of 1.5 km/h and a 50.8 mm pulley, the average cutting efficiency was 97.43% at a cutting height of 50 mm, increasing marginally to 97.49% at a cutting height of 75 mm. Similarly, at the same speed but using a 101.6 mm pulley, the average cutting efficiency was 97.32% at 50 mm and 97.38% at 75 mm.

Figure 6a shows that at a speed of 2 km/h and a pulley diameter of 50.8 mm, the average cutting efficiency was 97.93% at 50 mm and 97.96% at 75 mm. Using a 76.2 mm pulley at the same speed results in an average cutting efficiency of 97.89% for 50 mm and 97.91% for 75 mm. With a 101.6 mm pulley, the average cutting efficiency was 97.70% at 50 mm and increased slightly to 98.10% at 75 mm.

In Figure 6a, at a faster forward speed of 2.5 km/h, utilizing a 50.8 mm pulley resulted in an average cutting efficiency of 98.24% at 50 mm, increasing to 98.29% at 75 mm. Using a 101.6 mm pulley at the same speed results in an average cutting efficiency of 98.11% at 50 mm, increasing to 98.13% at 75 mm. With a 76.2 mm pulley, the average cutting efficiency was 98.28% at 50 mm and increased to 98.29% at 75 mm. These findings highlight a positive correlation between forward speed and conveyor driving pulley size, which affects cutting efficiency. This correlation is attributed to the increase in cutting efficiency with the forward speed of the harvester, as represented by Figure 5.

Effect of Forward Speed and Cutting Height on Cutting Efficiency of Coriander

Figure 6b shows how forward speed and cutting height affect the cutting efficiency of the coriander field. At a forward speed of 1.5 km/h and a cutting height of 50 mm, the average cutting efficiencies were as follows: 97.61% with a 101.6 mm conveyor driving pulley, 97.63% with a 76.2 mm conveyor driving pulley, and 97.65% with a 50.80 mm conveyor driving pulley. With a forward speed of 1.5 km/h and a cutting height of 75 mm, the average cutting efficiency was 97.62% with a 101.6 mm conveyor driving pulley, 97.65% with a 76.2 mm conveyor driving pulley, and 97.7% with a 50.8 mm conveyor driving pulley.

Figure 6b shows that at a harvester speed of 2.5 km/h and a cutting height of 50 mm, the average cutting efficiencies were 97.7% with a 101.6 mm conveyor driving pulley, 97.8% with a 76.2 mm conveyor driving pulley, and 97.8% with a 50.8 mm conveyor driving pulley. At a forward speed of 2.5 km/h and a cutting height of 75 mm, the average cutting efficiency was 97.80% for a 101.6 mm conveyor driving pulley, 97.83% for a 76.2 mm conveyor driving pulley, and 97.82% for a 50.8 mm conveyor driving pulley.

According to the findings, the cutting effectiveness of the self-propelled battery-operated coriander harvester was affected by the combination of forward speed and cutting height. The second level of cutting height resulted in optimal cutting efficiency and increased forward speed. Higher values for forward speed and cutting height further enhance cutting efficiency. A lesser forward speed and cutting height, on the other hand, result in lower cutting efficiency. Notably, lower forward speed with greater cutting height has a lesser impact on cutting efficiency than when both values are higher. The combination of low forward speed and high cutting height results in the lowest cutting efficiency.

Effect of Cutting Height and Conveyor Driving Pulley on Cutting Efficiency

Figure 6c shows the influence of cutting height and conveyor driving pulley on coriander crop cutting efficiency. At a forward speed of 1.5 km/h, a 101.6 mm conveyor drive pulley achieves a cutting efficiency of 97.25% at 75 mm and 97.21% at 50 mm. Similarly, at the same speed, a 76.2 mm conveyor driving pulley has an average cutting efficiency of 97.29% at 75 mm and 97.21% at 50 mm. Using a 50.8 mm conveyor driving pulley at the same speed yields cutting efficiencies of 97.35% at 75 mm and 97.31% at 50 mm.

According to Figure 6c, at a forward speed of 2 km/h, using a 101.6 mm pulley on the conveyor drive mechanism results in cutting efficiencies of 97.91% at a cutting height of 75 mm and 97.79% at a cutting height of 50 mm. Under identical conditions, a 76.2 mm pulley on the conveyor drive system achieves a cutting efficiency of 97.95% at 75 mm and 97.86% at 50 mm. Using a 50.8 mm pulley on the conveyor’s drive mechanism at the same speed results in cutting efficiencies of 98.96% at 75 mm and 97.91% at 50 mm.

In Figure 6c, the analysis focuses on the effect of different pulley diameters on the conveyor driving mechanism and cutting height on cutting efficiency, particularly at a forward speed of 2.5 km/h. The cutting efficiency of a 101.6 mm pulley is 98.59% at 75 mm and 98.54% at 50 mm. Similarly, a 76.2 mm pulley has an average cutting efficiency of 98.65% at 75 mm cutting height and 98.6% at 50 mm cutting height. Using a 50.8 mm pulley under the same conditions yields a cutting efficiency of 98.70% at 75 mm and 97.65% at 50 mm. It is worth noting that altering the cutting height has a more significant impact on cutting efficiency. Increasing the cutting height improves cutting efficiency by providing more ground clearance, which allows the cutting unit to move freely. This discovery emphasises the need to adjust cutting height to achieve greater cutting efficiencies, and the data in Figure 6c provides detailed information on how different pulley sizes affect these efficiencies at a given forward speed.

3.3.2. Conveying Loss, (%)

The conveying loss percentage for different forward speeds, various sizes of conveyor driving pulleys, and different levels of cutting height has been plotted in Figure 7 and Figure 8. The average of the observations for conveying loss at each treatment was included in

Table 6. Average of conveying loss at different levels of variables in coriander.

S. No	Forward Speed, (km/h)	Conveyor Driving Pulley Size, (mm)	Conveying Loss, (%)
			Cutting Height, (mm)
			50	75
1	1.5	101.6	1.27	1.33
2		76.2	1.08	1.21
3		50.8	0.91	0.98
4	2	101.6	1.31	1.36
5		76.2	1.07	1.23
6		50.8	1	1.32
7	2.5	101.6	1.32	1.38
8		76.2	1.12	1.25
9		50.8	0.98	1.02

.

The conveying loss rate during coriander harvesting averaged 1.11%, with a standard deviation of 0.0321 and a coefficient of variation (CV) of 2.90%.

The projected R² of 0.8562 was comparable to the corrected R² of 0.9599, with a difference of less than 0.2. Adequate precision quantifies the signal-to-noise ratio. A ratio larger than four was desired. A ratio of 18.169 suggests that the signal is acceptable. According to

Table 7. Influence of design variables on conveying loss of the experimentally developed harvester (ANOVA).

Source	Sum of Squares	DF	Mean Square	F-Value	p-Value
Model	0.4798	10	0.0480	46.43	<0.0001	Significant
A-Forward speed, (km/h)	0.0013	1	0.0013	1.29	0.2855	*
B-Conveyor driving pulley size, (mm)	0.4453	2	0.2227	215.47	<0.0001	*
C-Cutting height, (mm)	0.0000	1	0.0000	0.0296	0.8672	*
AB	0.0026	2	0.0013	1.23	0.3359	*
AC	0.0004	1	0.0004	0.3496	0.5689	*
BC	0.0013	2	0.0006	0.6125	0.5631	*
A2	0.0000	1	0.0000	0.0127	0.9129	*
Residual	0.0093	9	0.0010
Lack of fit	0.0066	4	0.0016	3.03	0.1277	Not significant
Pure error	0.0027	5	0.0005
Cor total	0.4891	19
Std. dev.		0.0321	R2		0.9810
Mean		1.11	Adjusted R2		0.9599
C.V. %		2.90	Predicted R2		0.8562
			Adequate precision		18.1690

‘*’: not statistical significance because most of those factors have high p-values (>0.05).

, the model F-value of 46.43 indicates that the model is significant. There was only a 0.01% chance that an F-value of this magnitude would occur owing to noise. p-values of less than 0.0500 suggest that model terms were significant. In this scenario, B was a vital model term. Values over 0.1000 imply that the model terms were not significant. The lack of fit F-value of 3.03 implies the lack of fit was not significant relative to the pure error. There was a 12.77% chance that a lack of fit F-value this large could occur due to noise. Non-significant lack of fit was good.

Final equation in terms of actual factors for conveying loss (%) in following conditions.

➢

Conveyor driving pulley size, (101.6 mm):

Cutting height, (50 mm) = 1.2418 + 0.0445156 A − 0.00899836 A²,

(14)

Cutting height, (75 mm) = 1.3033 + 0.0177668 A − 0.00899836 A².

(15)

➢

Conveyor driving pulley size, (76.2 mm):

Cutting height, (50 mm) = 1.03259 + 0.0515764 A − 0.00899836 A²,

(16)

Cutting height, (75 mm) = 1.06117 + 0.0248276 A − 0.00899836 A².

(17)

➢

Conveyor driving pulley size, (50.8 mm):

Cutting height, (50 mm) = 0.691289 + 0.13243 A − 0.00899836 A²,

(18)

Cutting height, (75 mm) = 0.75613 + 0.105681 A − 0.00899836 A².

(19)

This equation should not be used to calculate the relative influence of each element, as the coefficients were scaled to match the units of all variables, and the intercept was not positioned at the center of the design space.

Effect of an Individual Variable on Conveying Loss, (%) of Coriander

Analyze the influence of forward speed on conveying loss % using Figure 7a. The average conveyance loss is 1.28% at the slowest forward speed of 1.5 km/h, and 1.30% at the fastest forward speed of 2.5 km/h. In a similar investigation (Tanti et al. 2019) [44], it was found that conveyance loss increased with forward speed. The graphic shows that conveyor loss increases with rising forward speeds, which is related to material slippage on the conveyor resulting from the increased forward speed.

Examine the link between conveyor driving pulley size and conveying loss in Figure 7b. Conveying loss was measured at 0.92% for a 50.8 mm conveyor driving pulley, 1.09% for a 76.2 mm pulley, and 1.29% for a 101.6 mm pulley. This investigation shows that the size of the conveyor’s driving pulley has a substantial impact on conveying loss. A larger conveyor driving pulley results in a greater conveyor speed, which in turn influences material slippage.

Figure 7c shows an investigation of the association between coriander plant cutting height from the ground and conveyance loss. At level 1 of B (50 mm) from the ground, the conveyance loss was 1.29%, which increased to 1.31% when the coriander cutting height was raised to level 2 of B (75 mm). This tendency is consistent with findings by Bawatharani et al. (2016) [45].

According to the findings, the coriander cutting height has only a minor influence on the transmission of loss in a developed, self-propelled, battery-powered coriander harvester. Conveyor loss was impacted by the cutting height from the ground, with a greater coriander plant cutting height resulting in a higher inclination of the conveyor, increasing the possibility of yield slippage. A lower cutting height, on the other hand, minimizes the inclination of the conveyor, allowing for improved yield retention and, as a consequence, less conveying losses in developed harvesters.

Effect of the Combination of Variables on Cutting Conveying Loss in Coriander Crop

Effect of Forward Speed and Selection of Conveyor Driving Pulley on Conveying Loss.

In Figure 8a, evaluate how forward speed and conveyor driving pulley size affect conveying loss. At a forward speed of 1.5 km/h and a 50.8 mm pulley, the average conveying loss was 0.80% at a cutting height of 50 mm, rising to 0.89% at 75 mm. Similarly, using a 76.2 mm pulley, the average conveying loss was 1.07% at 50 mm and increased to 1.1% at 75 mm. Using a 101.6 mm pulley at the same speed, the average conveying loss was 1.26% at 50 mm and slightly higher at 75 mm.

Figure 8a shows that at a forward speed of 2 km/h, using a 50.8 mm pulley results in an average conveying loss of 0.91% at a ground clearance of 50 mm, increasing to 0.94% at 75 mm. Using a 101.6 mm pulley at the same speed, the average conveying loss was 1.29% at 50 mm and 1.35% at 75 mm. At a similar speed and with a 76.2 mm pulley, the average conveying loss was 1.06% at 50 mm and 1.075% at 75 mm.

Figure 8a shows that at a greater forward speed of 2.5 km/h, using a 50.8 mm pulley resulted in an average conveying loss of 0.96% at a ground clearance of 50 mm, increasing to 0.98% at 75 mm. With a 76.2 mm pulley, the average conveying loss was 1.06% at 50 mm and increased to 1.12% at 75 mm. Using a 101.6 mm pulley at the same speed, the average conveying loss was 1.29% at 50 mm and 1.39% at 75 mm.

Overall, the data indicate that conveying loss increases with forward speed and conveyor driving pulley size, as higher forward speed and larger driving pulley size result in increased conveyor speed, which in turn impacts material slippage. Both forward speed and the conveyor driving pulley have a considerable influence on conveyor loss. Higher values of both factors lead to higher loss than other combinations. When both the forward speed and the driving pulley were reduced, the conveyor loss decreased. Furthermore, the influence of each parameter alone results in reduced conveyance losses than when both values are significant.

Effect of Forward Speed and Cutting Height on Conveying Loss.

Figure 8b depicts the influence of forward speed and cutting height on conveyance loss. With a harvester speed of 1.5 km/h and a cutting height of 50 mm, the average conveying losses were 1.28% with a 101.6 mm conveyor driving pulley, 1.07% with a 76.2 mm conveyor driving pulley, and 0.88% with a 50.8 mm conveyor driving pulley. Similarly, with a forward speed of 1.5 km/h and a cutting height of 75 mm, the average conveying losses were 1.31% with a 101.6 mm conveyor driving pulley, 1.08% with a 76.2 mm conveyor driving pulley, and 0.90% with a 50.8 mm conveyor driving pulley.

Figure 8b shows that at a higher harvester speed of 2 km/h and a cutting height of 50 mm, the average conveying losses were 1.28% with a 101.6 mm conveyor driving pulley, 1.07% with a 76.2 mm conveyor driving pulley, and 0.91% with a 50.8 mm conveyor driving pulley. At the same speed and cutting height of 75 mm, the average conveying losses were 1.31% with a 101.6 mm conveyor driving pulley, 1.09% with a 76.2 mm conveyor driving pulley, and 0.94% with a 50.8 mm conveyor driving pulley.

Figure 8b shows that at a forward speed of 2.5 km/h and a cutting height of 50 mm, the average conveying losses were 1.29% with a 101.6 mm conveyor driving pulley, 1.06% with a 76.2 mm conveyor driving pulley, and 0.95% with a 50.8 mm conveyor driving pulley. With the same speed and cutting height of 75 mm, the average conveying loss was 1.27% for a 101.6 mm conveyor driving pulley, 1.10% for a 76.2 mm conveyor driving pulley, and 0.95% for a 50.8 mm conveyor driving pulley. The harvester’s conveyance loss was determined by its forward speed and cutting height. Raised harvester speed results in increased slippage on the conveyor, while higher cutting height leads to greater conveyor inclination, contributing to heightened conveying losses.

Effect of Cutting Height and Conveyor Driving Pulley on Conveying a Loss of Coriander Crop.

In Figure 8c, using a 101.6 mm conveyor driving pulley with a cutting height of 50 mm resulted in conveying losses of 1.28%, 1.29%, and 1.31% at forward speeds of 1.5 km/h, 2 km/h, and 2.5 km/h, respectively. At the same cutting height, a 76.2 mm driving pulley results in conveyance losses of 1.08% at 1.5 km/h, 1.1% at 2 km/h, and 1.15% at 2.5 km/h. Similarly, using a 50.8 mm conveyor pulley and the same cutting height, losses were 0.86% at 1.5 km/h, 0.92% at 2 km/h, and 0.96% at 2.5 km/h.

According to Figure 8c, using a 101.6 mm conveyor driving pulley with a cutting height of 75 mm resulted in conveying losses of 1.30%, 1.32%, and 1.34% for forward speeds of 1.5 km/h, 2 km/h, and 2.5 km/h, respectively. At the same cutting height, a 76.2 mm conveyor driving pulley results in conveying losses of 1.1% at 1.5 km/h, 1.14% at 2 km/h, and 1.169% at 2.5 km/h. Similarly, using a 50.8 mm conveyor driving pulley and the same cutting height, conveying losses were 0.89% at 1.5 km/h, 0.95% at 2 km/h, and 0.98% at 2.5 km/h.

Conveyor losses are impacted by both pulley size and cutting height, with increased cutting height and conveyor driving pulley directly affecting these losses. Elevated cutting height increases conveyor inclination, while greater pulley size increases conveyor speed, both of which have a negative influence on the conveyor and result in increased conveyor losses.

3.3.3. Harvesting Efficiency (%)

The harvesting efficiency percent for different forward speeds, different sizes of convseyor driving pulleys and different levels of cutting height have been plotted in Figure 9 and Figure 10. The average of the observations for harvesting efficiency at each treatment was included in

Table 8. Average of harvesting efficiency at different levels of variables on harvesting efficiency.

S. No	Forward Speed, (km/h)	Conveyor Driving Pulley Size, (mm)	Harvesting Efficiency, (%)
			Cutting Height, (mm)
			50	75
1	1.5	101.6	96	96.35
2		76.2	96.54	96.74
3		50.8	96.6	96.77
4	2	101.6	96.84	96.98
5		76.2	97.02	96.99
6		50.8	97.18	97.4
7	2.5	101.6	97.46	97.48
8		76.2	97.65	97.69
9		50.8	97.85	97.92

.

The standard deviation, mean, and coefficient of variation (%) for coriander harvesting efficiency were 0.0660, 96.80, and 0.0681, respectively. The predicted R² of 0.9435 was comparable to the adjusted R² of 0.9847, with a difference of less than 0.2. Adequate precision quantifies the signal-to-noise ratio. A ratio larger than four was preferred. A ratio of 36.757 suggests a good signal. This model can help you explore the design space.

From

Table 9. Influence of design variables on the harvesting efficiency of an experimentally developed harvester (ANOVA).

Source	Sum of Squares	DF	Mean Square	F-Value	p-Value
Model	5.38	10	0.5377	123.57	<0.0001	significant
A-Forward speed, (km/h)	4.93	1	4.93	1132.83	<0.0001
B-Conveyor driving pulley size, (mm)	0.7423	2	0.3711	85.29	<0.0001
C-Cutting height, (mm)	0.0002	1	0.0002	0.0358	0.8541
AB	0.0005	2	0.0002	0.0537	0.9480
AC	0.0014	1	0.0014	0.3273	0.5813
BC	0.0004	2	0.0002	0.0514	0.9502
A2	0.0222	1	0.0222	5.11	0.0502
Residual	0.0392	9	0.0044
Lack of fit	0.0227	4	0.0057	1.72	0.2819	Not significant
Pure error	0.0165	5	0.0033
Cor total	5.42	19
Std. dev.		0.0660	R2		0.9910
Mean		96.80	Adjusted R2		0.9847
C.V. %		0.0681	Predicted R2		0.9435
			Adequate precision		36.757

, The model F-value of 123.57 indicates that the model was significant. There was only a 0.01% chance that an F-value of this magnitude would occur owing to noise. p-values of less than 0.0500 suggest that model terms were significant. In this instance, A and B were important model terms. Values over 0.1000 imply that the model terms were not significant. The F-value of 1.72 indicates that the lack of fit was not statistically significant in comparison to the pure error. There was a 28.19% possibility that a significant lack of fit F-value may be caused by noise. The lack of fit was not considerable, which was fortunate.

The final equation in terms of actual factors for harvesting efficiency (%) in the following conditions:

➢

Conveyor driving pulley size, (101.6 mm):

Cutting height, (50 mm) = 95.3697 − 0.177356 A + 0.370805 A²,

(20)

Cutting height, (75 mm) = 95.2772 − 0.124253 A + 0.370805 A².

(21)

➢

Conveyor driving pulley size, (76.2 mm):

Cutting height, (50 mm) = 95.6568 − 0.187586 A + 0.370805 A²,

(22)

Cutting height, (75 mm) = 95.5639 − 0.134483 A + 0.370805 A².

(23)

➢

Conveyor driving pulley size, (50.8 mm):

Cutting height, (50 mm) = 95.9516 − 0.219195 A + 0.370805 A²,

(24)

Cutting height, (75 mm) = 95.8338 − 0.166092 A + 0.370805 A².

(25)

This equation should not be used to calculate the relative influence of each element, as the coefficients were scaled to match the units of each factor, and the intercept was not positioned at the center of the design space.

Effect of the Individual Variable on Harvesting Efficiency in Coriander Treatment

Figure 9a depicts the effect of forward speed on harvesting efficiency %. The average harvesting efficiency ranges from 96.19% at the slowest harvesting forward speed of 1.5 km/h to 97.50% at the fastest harvesting forward speed of 2.5 km/h, and 96.41% at a forward speed of 2 km/h. According to research by (Younis et al. 2012) [39], similar findings were seen, with harvesting efficiency increasing with the forward speed of the created self-propelled coriander harvester. Figure 9a shows a favourable association between harvesting efficiency and higher forward speed of the designed coriander harvester.

Using Figure 9b, assess the relationship between conveyor driving pulley size and harvesting efficiency of the proposed coriander harvester. Harvesting efficiencies were measured at 96.50% for a 101.6 mm pulley, 96.77% for a 76.2 mm pulley, and 96.99% for a 50.8 mm pulley driving the conveyor. The trend suggests that the selection of conveyor-driving pulleys has a minor impact on harvesting efficiency.

Figure 9c examines the link between cutting height and harvesting efficiency. At a coriander cutting height of 50 mm from the ground, harvesting efficiency is 96.7%, with a modest rise to 96.75% when the cutting height is increased to 75 mm. The cutting height has a significant impact on harvesting efficiency, with higher cutting heights contributing to increased efficiency. This finding is consistent with comparable research findings by Atallah (2014) [43], which also found that increasing cutting height was associated with improved harvesting efficiency. The increased cutting height enables smoother operation of the harvester, thereby improving harvest efficiency.

Effect of the Combination of the Variables on Harvesting Efficiency in Coriander Crop

Effect of Forward Speed and Selection of Conveyor Driving Pulley on Harvesting Efficiency.

From Figure 10a, study the influence of forward speed and conveyor driving pulley size on coriander crop harvesting efficiency. At a forward speed of 1.5 km/h and a 50.8 mm pulley, the average harvesting efficiency was 96.42% at a cutting height of 75 mm, but dropped to 96.45% at 50 mm. Similarly, using a 76.2 mm pulley, harvesting efficiency averaged 96.4% at 50 mm and increased to 96.45% at 75 mm. Using a 101.6 mm pulley at the same speed, the average harvesting efficiency was 95.93% at 70 mm and somewhat lower at 50 mm.

According to Figure 10a, at a forward speed of 2 km/h and a pulley diameter of 50.8 mm, the average harvesting efficiency was 97.01% at a cutting height of 50 mm, and it increased to 97.05% at 75 mm. Using a 101.6 mm pulley at the same speed, the average harvesting efficiency was 96.41% at 50 mm and 96.5% at 75 mm. Using a 76.2 mm pulley at the same speed, the average harvesting efficiency was 96.79% at 50 mm and 96.83% at 75 mm.

According to Figure 10a, using a 50.8 mm pulley and a greater forward speed of 2.5 km/h resulted in an average harvesting efficiency of 97.27% at a cutting height of 50 mm, increasing to 97.7% at 75 mm. With a 76.2 mm pulley, the average harvesting efficiency was 97.50% at 50 mm and increased to 97.52% at 75mm. Using a 101.6 mm pulley at the same speed, the average harvesting efficiency was 97.24% at 50 mm and 97.32% at 75 mm.

According to the findings, the best harvesting performance was achieved by combining a greater forward speed with a smaller conveyor driving pulley. Larger pulley sizes increase conveyor speed, resulting in larger conveyor losses and decreased harvesting efficiency. Higher harvesting speed increases harvesting efficiency, which results in reduced harvesting time. As a result, both forward speed and conveyor driving pulley have a substantial effect on harvesting efficiency.

Effect of Forward Speed and Cutting Height on Harvesting Efficiency.

Figure 10b investigates the relationship between forward speed and cutting height on harvesting efficiency. With a forward speed of 1.5 km/h and a cutting height of 50 mm, the average harvesting efficiency was 96.18% with a 101.6 mm conveyor driving pulley, 96.3% with a 76.2 mm conveyor driving pulley, and 96.9% with a 50.8 mm conveyor driving pulley. Similarly, at a forward speed of 1.5 km/h and a cutting height of 75 mm, the average harvesting efficiency was 96.23% with a 101.6 mm conveyor driving pulley, 96.34% with a 76.2 mm conveyor driving pulley, and 97.15% with a 50.8 mm conveyor drive pulley.

Figure 10b shows that at a forward speed of 2 km/h and a cutting height of 50 mm, the average harvesting efficiencies were 96.5% with a 101.6 mm conveyor driving pulley, 96.95% with a 76.2 mm conveyor driving pulley, and 97.1% with a 50.8 mm conveyor driving pulley. At the same speed and cutting height of 75 mm, the average harvesting efficiency was 96.7% with a 101.6 mm conveyor driving pulley, 96.99% with a 76.2 mm conveyor driving pulley, and 97.12% with a 50.8 mm conveyor driving pulley.

According to Figure 10b, at a higher forward speed of 2.5 km/h and a cutting height of 50 mm, the observed average harvesting efficiencies were 96.7% with a 101.6 mm conveyor driving pulley, 97.2% with a 76.2 mm conveyor driving pulley, and 97.6% with a 50.8 mm conveyor driving pulley. At the same speed and cutting height of 75 mm, mean harvesting efficiencies were 97.1% for a 101.6 mm conveyor driving pulley, 97.4% for a 76.2 mm conveyor driving pulley, and 97.7% for a 50.8 mm conveyor driving pulley of the designed coriander harvester.

The harvesting efficiency of the self-propelled battery-powered coriander harvester was strongly influenced by the combination of forward speed and cutting height. Harvesting efficiency was considerably impacted by both forward speed and cutting height. The combination of high forward speed and cutting height resulted in optimal harvesting efficiency. Lower forward speed and cutting height parameters diminish harvesting efficiency. Furthermore, a greater forward speed with a lower cutting height results in lesser efficiency compared to circumstances when both are higher. Surprisingly, the effect on harvesting efficiency was insignificant when a lower forward speed was combined with increased cutting height.

Effect of Cutting Height and Conveyor Driving Pulley on Harvesting Efficiency.

According to Figure 10a, using a 101.6 mm conveyor driving pulley at a 50 mm coriander cutting height resulted in average harvesting efficiencies of 95.9%, 96.49%, and 97.24% at forward speeds of 1.5 km/h, 2 km/h, and 2.5 km/h, respectively. Similarly, utilizing the same pulley with a 75 mm coriander cutting height yielded average harvesting efficiency of 95.92% at 1.5 km/h, 96.51% at 2 km/h, and 97.28% at 2.5 km/h.

Figure 10b shows that using a 76.2 mm conveyor driving pulley at a 50 mm cutting height results in average harvesting efficiencies of 95.20%, 96.73%, and 97.50% for forward speeds of 1.5 km/h, 2 km/h, and 2.5 km/h, respectively. Similarly, utilizing the same pulley with a 75 mm coriander cutting height yielded average harvesting efficiency of 96.19% at 1.5 km/h, 96.79% at 2 km/h, and 97.54% at 2.5 km/h.

According to Figure 10c, using a 50.8 mm conveyor driving pulley at a cutting height of 50 mm resulted in average harvesting efficiencies of 96.45%, 96.99%, and 97.72% at forward speeds of 1.5 km/h, 2 km/h, and 2.5 km/h, respectively. Similarly, using the same 50.8 mm pulley with a 75 mm cutting height results in average harvesting efficiency of 96.49% at 1.5 km/h, 96.98% at 2 km/h, and 97.7% at 2.5 km/h. These findings highlight the influence of conveyor driving pulley size and cutting height on harvesting efficiency at varying coriander harvesting forward speeds.

The combination of conveyor driving pulley size and coriander cutting height from the ground in the coriander field greatly influenced harvesting efficiency. However, when the conveyor driving pulley was lowered and the cutting height was increased, harvesting efficiency improved. Conversely, a larger conveyor driving pulley with a lower cutting height reduces efficiency due to greater conveying loss and harvester slippage. Furthermore, a combination of a larger conveyor driving pulley size and a higher coriander cutting height affects harvesting efficiency by increasing conveying loss, while improving efficiency through enhanced ground cutting height. A lower coriander cutting height, combined with a smaller conveyor driving pulley, has a minimal influence on harvesting efficiency. Lower cutting height reduces efficiency, while a smaller conveyor driving pulley increases it. As a result, the best combination for harvesting with a self-propelled battery-operated coriander harvester always includes a lower conveyor driving pulley size and the maximum coriander cutting height from the ground.

3.3.4. Optimum Value of Each Independent Variable for Coriander Crop

The optimum level of the independent variables under study was considered to be that at which the coriander harvester achieved a higher percentage of cutting efficiency, a lower percentage of conveying losses, a lower amount of power consumed, and a more effective field capacity. The harvester testing across a speed range was 1.5 to 2.5 km/h, coupled with machine level variations using 50.8 mm to 101.6 mm pulleys for conveyor drive and two cutting height levels. Within these conditions, cutting efficiency ranged from 97.25% to 98.68%, and conveying loss spanned from 0.87% to 1.35%. Notably, the top five most desirable solutions among the 100 outcomes were specifically highlighted in

Table 10. Optimised five solutions from a pool of 100 effects of the independent variable for effective harvesting efficiency.

Forward Speed, (km/h)	Conveyor Driving Pulley Size, (mm)	Cutting Height, (mm)	Cutting Efficiency, (mm)	Conv Eying Loss, (%)	Harvesting Efficiency, (mm)	Desirability
1.647	Level 3 of A	Level 2 of B	97.471	0.906	96.566	1.00	Selected
2.500	Level 2 of A	Level 1 of B	98.610	1.105	97.505	1.00
2.000	Level 1 of A	Level 1 of B	97.792	1.295	96.498	1.00
2.000	Level 2 of A	Level 2 of B	97.852	1.075	96.778	1.00
1.500	Level 2 of A	Level 1 of B	97.300	1.090	96.210	1.00

.

Based on the RAMPS and red coloured circle marks presented in Figure 11, optimal operating conditions for the harvester, resulting in optimal harvesting efficiency, were identified at a forward speed of 1.64 km/hr, a conveyor driving pulley of level 3 of A (50.8 mm), and a cutting height at level 2 of B (75 mm). Under these conditions, the resultant cutting efficiency reaches 97.47%, conveying loss is minimised to 0.906%, and harvesting efficiency peaks at 96.566%. This finding suggests that achieving this specific combination of forward speed, cutting height and conveyor driving pulley size can enhance the overall performance of the harvester in terms of harvesting efficiency.

3.3.5. Effect of Forward Speed on Actual Field Capacity and Theoretical Field Capacity of the Harvester in Coriander

The harvester moves at a speed of 1.5 km/h, covering an area of 0.114 ha/h. As the speed increases to 2 km/h, the coverage expands to 0.164 ha/h and further increases to 0.22 ha/h at the fastest speed, which was 2.5 km/h (Figure 12). The developed self-propelled battery-operated coriander harvester demonstrated a higher adequate field capacity when compared to the practical field capacity of the rotary leafy vegetable harvester developed by Singh et al. (2020) [46] in the coriander field. From Figure 13, field efficiency increases proportionally with the acceleration of forward speed, registering values of 76%, 82%, and 88% at forward speeds of 1.5 km/h, 2 km/h, and 2.5 km/h, respectively. The developed harvester exhibited superior field efficiency when compared to the field efficiency of a tractor-operated leafy vegetable harvester, which operated at a speed of 2.70 km/h and a knife speed of 297 rpm, as developed by Olowojola et al. (2011) [47].

3.3.6. Performance of the Harvester at the Optimised Machine Variable of Coriander Crop

Table 11. Performance of the harvester at the optimised machine variable of coriander crop.

S. No	Parameters	Average
1	Harvesting efficiency, (%)	97.24
2	Cutting efficiency, (%)	98.2
3	Conveying loss, (%)	0.96
4	Theoretical field capacity, (ha/h)	0.16
5	Actual field capacity, (ha/h)	0.131
6	Field efficiency, (%)	81.8
6	Working hours, (h)	6.6

shows that under optimal conditions, the harvester had a harvesting efficiency of 97.24%, a cutting efficiency of 98.2%, a minimal conveying loss of 0.96%, a theoretical field capacity of 0.16 ha/h, an actual field capacity of 0.131 ha/h, and an overall field efficiency of 81.8% for coriander. Furthermore, with a full battery, the harvester sustained a working time of 6.6 h.

3.3.7. Effect of Harvesting with Developed Harvester on Yield of Selected Crops

Coriander’s initial harvesting yield was 66.08 q/ha after 42 DAS. The second-time yield was 68.21 q/ha after 63 DAS, while the third-time yield was 65 q/ha after 82 DAS. Compared to the yield from the field chosen by Biswas (2023) [48], the created harvester produced a larger yield. The outstanding performance was due to the use of the broadcast technique, a high seed rate, hybrid seed, and timely meeting of water and plant requirements.

3.4. Economic Evaluation of the Developed Self-Propelled Battery-Operated Coriander Harvester

The total capital cost of the self-propelled, battery-operated coriander harvester was computed by summing the costs associated with all the parts used in its fabrication. The harvester’s cost of operation was calculated by adding fixed and variable expenditures. The computed capital cost for the planned harvester was Rs. 60,807. The whole fixed cost is 9.83 Rs./h, and the total variable cost is 91.52 Rs./h, resulting in a total cost of the constructed machine per hour of 101.35 Rs. The benefit–cost ratio was 39.04. The use of a harvester in coriander production resulted in a cost reduction of Rs. 7179.86/ha, a 95.73% drop. Furthermore, it saved 194.16 h/ha, representing a 97.08% reduction in time.

4. Conclusions

This self-propelled battery-powered coriander harvester can accomplish the planned design function through actual field tests, resulting in mechanised coriander harvesting. Harvesting performance is several times higher than traditional harvesting of coriander, and the coriander harvester has the benefits of a simple construction, easy operation, and maintenance, but it also greatly reduces overall energy consumption and labour charges. The design and development of this self-propelled, battery-powered coriander harvester are critical for improving coriander efficiency, reducing labour intensity, promoting the mechanisation of coriander cultivation, reducing physical strain among workers using traditional harvesting methods, reducing environmental pollution, and accelerating the progress of agricultural activities. The harvester had a harvesting efficiency of 97.24%, a cutting efficiency of 98.2%, a minimal conveying loss of 0.96%, a theoretical field capacity of 0.16 ha/h, an actual field capacity of 0.131 ha/h, and an overall field efficiency of 81.8% for coriander.