Abstract:In order to further improve the flexibility of mountain orchard transport,this paper proposes a cable-towed trackless transporter for hilly orchard.The low-altitude transportation in orchard is realized by setting up the pile point on the hilly orchard,controlling the movement of paralleled steel cable.According to the actual terrain situation in Ganzhou,the actual standard used by the system model is that the horizontal distance between two piles located at the top of two mountains is set at 3 200 m,the mountain height is set at 240 m,and the height difference between adjacent mountains is set within 10-50 m.According to the actual situation of the slope angle,the inclination angle of the transportation route down the mountain was set as 36.87° The total weight of the fruit basket filled with fruit picked was set at 100 kg.The main transportation process of the transporter is as follows:the fruit basket filled with fruit picked is placed on the pile platform at the top of the hill and suspended on the hook at the end of the cable.Each hook is connected to 2-3 cables,and the other end of each cable is connected to a drum connected to the motor and the reducer.Each cable is controlled by a separate motor,and the speed of the cable is controlled by motor speed control,so that the fruit basket can be transported downhill in different paths and speeds.In order to reduce the swing deviation caused by the own mass and motion of cable and eliminate the response hysteresis and critical jitter of system,an independent lifting control device is set up for the fruit basket.The only control is realized by installing the button at the end of the sling to ensure the temporary lifting of the fruit basket not be affected by the movement of cable.Based on three-dimensional route model,the parallel mechanism consists of three piles,and the working scope of the equipment is the triangular area enclosed by the piles.For the convenience of analysis and calculation,the transportation routes of all fruit baskets in the model are approximated as straight lines.By analyzing the motion model of the device,the relation of the motion speed between the three cables is obtained to provide a theoretical basis for regulating motor speed.By a transport mechanics model the traction on the cable is about time with the dual function of the angle.The horizontal distance is flexible to set parameters,the angle and subject to change with the change of the three-dimensional length,velocity can be obtained to adjust the parameters according to the practical application of control motor.The results of simulating the model with Matlab software showed that the initial speeds of cable b and c changed within 1-2 m/s and gradually decreased with the increase of time when cable a kept moving at 2.5 m/s for the three-pile parallel mechanism of transportation.The initial velocity of the cable decreased as the deflection angle increased.In the process of transportation with a uniform drop of the fruit basket,the traction force on cable a,b and c gradually increased with the increase of time.The increase rate of cable a is the largest,while the increase rates of cable b and c are the same basically but less than that of cable a.Within the scope of the changing the angle α,when the angle is the median cable on a traction,the limit value is the biggest when the cable on both sides of a traction is the smallest.The cable force on b decreases gradually with the increase of angle,and is negatively correlated with the angle.The cable force on the c increases with the increase of angle.The simulation data obtained by modeling fits with the mathematical model,indicating that the model is correct and reliable.The independent lifting sling system controlling the rise and fall of fruit basket make the whole transport process streamlined.Orchard topographic simulation is based on establishing a transporter mechanics model and numerical simulation analysis.The results of simulation showed that the speed and traction on the cable changed slowly and evenly during transportation under the different transportation path angle.The method of analyzing the parallel mechanism with three-dimensional route model can be used to simulate the transportation between two and several hilly orchard.The parallel mechanism guarantees the stability of the system during operation and its flexibility will expand the scope of applying the transporter further.