Design And Testing Of An Embedded-Wire Single-rail Transport Vehicle

China is the world’s largest producer of citrus fruits with abundant resources of citrus fruit tree cultivation.However,most of the citrus growing areas are located in hilly and sloping areas in South China,which poses challenges for the transportation of citrus fruits and materials.To address this issue,researchers from both domestic and international institutions have developed a series of fuel-powered and electric-powered track transporters,which has effectively improved transportation efficiency.But fuel-powered track transporters have disadvantages such as high fuel costs and significant emissions,and electric-powered track transporters have some problems,such as power supply,short range,and low carrying capacity.Moreover,existing track transporters are mainly designed for small-scale transportation and lack the ability for multi-track coordination.In order to cope with these challenges,this study has developed an embedded-wire single-track transporter with high load-carrying capacity,stable power supply and suitability for transportation in large-scale orchards.The main research contents are as follows:(1)Determination of the overall design scheme.The traction head consisted of a power source and a transmission system,which used a combination of belt,worm gear and drive wheel to make the machine structure layout more compact.To meet the requirements of stable power supply,a special-shaped track that integrated driving and power transmission functions was developed and the voltage loss during power transmission was calculated to formulate corresponding voltage compensation measures.Based on the bending rules of track laying,a rolling current collection device that automatically adjusted its contact posture according to the track trend was designed.The force analysis of the device was carried out to determine specific parameters of the compression spring.Meanwhile,to avoid overheating and damage of the contact head due to contact resistance,the contact temperature rise was calculated to be 16.97 ℃,which met the requirement of use.Through the analysis of four typical track switching schemes,the track-changing device suitable for mountainous orchard transportation was proposed,and the model of electric push rod was determined based on the force analysis during operation.The control circuit of the transportation system was constructed,including power supply circuit,traction head control circuit,and track switching control circuit,with the addition of a wireless remote control module for remote control functionality.(2)Analysis and verification of key components using simulation software.The stress and strain analysis of the special-shaped track and track joint were conducted by using the statics module in ANSYS.The results showed that the stress values and maximum deformation values were below the allowable limits,meeting the usage requirements.General modal analysis and prestressed modal analysis were performed on the track,and the natural frequencies of the track under different loading conditions showed slight fluctuations.The minimum first-order natural frequency under various working conditions was 69.295 Hz,which met the usage requirements.The dynamic analysis of the transporter’s transmission was conducted by using ADAMS software,and the results showed that the mechanical characteristics of front-wheel drive transportation were superior to rear-wheel drive transportation.Furthermore,through two-factor simulation analysis,it could be inferred that the slope factor had a more significant impact on the transportation performance of the transporter than the payload factor.The temperature field simulation of the contact head was performed by using Fluent software,and the results showed that the temperature decreased upward along the contact point between the copper wheel and the wire.The maximum temperature rise was 16.33 ℃,which was consistent with the theoretical calculation value.(3)Prototype fabrication and performance testing.Flat terrain running tests were conducted.The results showed that the speed of the transporter during outbound trips ranged from 0.683 m/s to 0.692 m/s,while the speed during inbound trips ranged from0.668 m/s to 0.676 m/s.The effect of payload on speed was minimal during flat terrain running,but the speed with outbound payload was slightly higher than the speed with inbound payload.Furthermore,hill climbing tests were conducted,and the results showed that the speed of the transporter fluctuated between 0.643 m/s and 0.690 m/s under different payloads.Payload had a significant impact on speed during hill climbing,but the transporter was still able to climb hills stably,meeting the usage requirements.Performance tests of the track-changing device were conducted,and the results showed that the track-changing device operated stably with good conditions of port docking.