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Currently, crop-harvesting is usually performed by agricultural machines called combines (combine harvesters). Due to the limited capacities of the combines, a grain cart is involved for transporting the grains from combines to the depot. If there are sufficient number of grain carts, each combine can go alongside with a grain cart for unloading. However, if the number of combines exceeds the number of grain carts, we have to consider the problem of scheduling the grain carts to unload all the combines. Moreover, most farmers prefer to unload the combine when it is harvesting in order to improve the efficiency. This indeed requires better coordination between the combines and grain cart so that the unloading process can be performed without any interruption. Based on the fact that the grain cart is primarily responsible for unloading grains, we explore the problem of motion planning and scheduling for an autonomous grain cart that serves multiple combines in a field.
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In this paper, we address a motion planning problem for an autonomous agricultural vehicle modeled as tractor-trailer system. We first present a numerical approach and a primitive-based approach for computing the time-optimal path based on given static initial and goal configurations. In the former approach, we define a value function for the entire state space. The value function is consistent with the time to reach goal configuration, and it is finally used to compute the optimal trajectory. In the latter approach, based on the regular and singular primitives, we present an algorithm to construct such primitives and derive the final path. Subsequently, we extend the results and present a dynamic motion planning strategy to accommodate the case of mobile target configuration. Finally, simulation results are provided to validate the feasibility and effectiveness of these techniques.
M. Zhang and S. Bhattacharya,
Logistics Motion Planning for Agricultural Vehicles. In
Asian Control Conference, 2015. Note: Under review.
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In this paper, we focus on the motion planning for an unloading agriculture vehicle. Based on the harvesting operations, we firstly present an unloading scheduling, considering the cases of single combine and multiple combines. The scheduling motivates us to minimize the travel time for the unloading vehicle to move between combines and depot. With this in mind, we present a numerical approach to obtain the time-optimal path when grain cart moves to a static configuration. In the dynamic case, we present a greedy algorithm which accommodates mobile target configuration. Finally, we provide simulations to demonstrate the feasibility and show the comparison between the performances of proposed techniques.
M. Zhang and S. Bhattacharya,
Unloading Motion Planning for Agricultural Vehicles. In
IFAC Workshop on Multi-Vehicle Systems, 2015. Note: Under review.
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In this paper, we address the scheduling and motion planning problem for an autonomous grain cart serving multiple combines. First, we propose a scheduling scheme which allows grain cart to unload all the combines without interruption in the harvesting activity. The schedule is presented for an arbitrary number of combines. Additionally, we present path planning analysis for the grain cart. The path of grain cart is composed of singular primitives and regular primitives which ensure local time-optimality. Finally, simulation results are provided to validate the feasibility of the proposed techniques.
M. Zhang and S. Bhattacharya,
Logistics Scheduling and Motion Planning for Agricultural Vehicles. In
IEEE International Conference on Robotics and Automation (ICRA), 2015. Note: Under review.
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