System and method for towing a trailer
View Patent ↗Systems for towing a trailer by a towing vehicle and a method for controlling such a system are disclosed. The systems and method are configured to maintain a constant towing load on the towing vehicle as well as optimizing other performance criteria such as fuel efficiency. The system comprises a closed loop controller, a towing arm assembly, a load measuring device, an electric hub motor, brakes, a motor controller and a brake controller disposed on the trailer. In another embodiment, two separate systems are installed, one on each side of the trailer. A load force feeds into a PID controller programmed with preset proportional, differential and integral parameters. The PID controller generates a command signal to either modulate the brakes or motor up or down depending on the sign of the command signal. A process output updates the system which continuously adjusts based on driving conditions.
1. A system for towing a trailer by a towing vehicle, said trailer comprising a first side containing at least one wheel and a second side containing at least one wheel, said system comprising:
at least one electric hub motor, said each electric hub motor being adapted for turning one wheel of the trailer, said electric hub motor being powered by at least one battery disposed in the trailer;
a towing arm assembly engaged with the trailer at one end and the towing vehicle at another end, said towing arm assembly being adapted for transmitting a mechanical load from the towing vehicle to the trailer;
a brake system adapted for applying a breaking force to said wheel;
a closed-loop controller disposed on the trailer, said controller being adapted for receiving and processing signals, said closed-loop controller comprising a summing junction, a logic control unit and a process controller; and
a load measuring device mounted on the towing arm assembly, said load measuring device being adapted for measuring and summing mechanical forces, said load measuring device also being adapted for transmitting a voltage proportional to a mechanical force to the logic control unit.
2. The system of claim 1 , wherein the brake system comprises mechanical brakes and regenerative brakes.
3. The system of claim 1 , wherein the logic control unit of the closed-loop controller comprises a proportional calculator, a differential calculator and an integral calculator.
4. The system of claim 3 , wherein the proportional calculator contains at least one preset proportional gain and a proportional algorithm, said differential calculator containing at least one preset differential gain and a differential algorithm, said integral calculator containing at least one preset integral gain and an integral algorithm.
5. The system of claim 1 , wherein the process controller comprises:
an electric hub motor controller adapted for receiving, processing and transmitting signals, said electric hub motor controller being adapted for modulating a speed of the electric hub motor;
a brake controller adapted for receiving, processing and transmitting signals, said brake controller being adapted for modulating braking of the trailer wheels.
6. The system of claim 1 wherein the towing vehicle is a bicycle.
7. The system of claim 1 , wherein the load measuring device comprises an S-type load cell having a top bar and a bottom bar.
8. The system of claim 7 , wherein the towing arm assembly comprises:
a front bar and a rear bar wherein a front portion of the front bar is engaged with the towing vehicle and wherein a rear portion of the rear bar is engaged with the trailer, said rear bar being positioned at a higher elevation relative to the front bar;
a first plate disposed at a first side of the front bar and the rear bar and a second plate disposed at a second side of the front bar and the rear bar, said front bar being pivotally affixed to the first plate and the second plate by a front pivoting axle and by a rear pivoting axle, said first side of the rear bar being permanently affixed to the first plate, said second side of the rear bar being permanently affixed to the second plate;
the S-type load cell being attachably mounted on a top surface of the front bar; and
a shaft attached to a front portion of the rear bar at one end, said shaft being threadably attached to the bottom bar of the S-type load cell.
9. The system of claim 3 , wherein the logic control unit comprises a PID controller.
10. A system for towing a trailer by a towing vehicle, said trailer comprising a first side and a second side, each of the first side and of the second side of the trailer comprising:
at least one wheel;
at least one electric hub motor, each electric hub motor being adapted for turning one wheel of the trailer, said electric hub motor being powered by at least one battery disposed in the trailer;
a load measuring device support assembly having a front arm and a rear arm, said rear arm of the load measuring device support assembly being engaged with the trailer, said load measuring device support assembly being adapted for containing a load measuring device, said rear arm being positioned at a higher elevation relative to the front arm;
a brake system adapted for receiving command signals and for applying a breaking force to said wheel;
a closed-loop controller, said controller being adapted for receiving and processing signals, said closed-loop controller comprising a summing junction, a logic control unit and a process controller;
a load measuring device mounted on the load measuring device support assembly, said load measuring device being adapted for measuring and summing mechanical loads, said load measuring device also being adapted for transmitting a mechanical force to the logic control unit;
said system also comprising a joining bar attached at one end to the front arm of the load measuring device support assembly of the first side of the trailer, said joining bar being attached at another end to the front arm of the load measuring device support assembly of the second side of the trailer, said system also containing a hitch bar attached at one end to the joining bar and to the towing vehicle at another end.
11. The system of claim 10 , wherein the load measuring device comprises an S-type load cell having a top bar and a bottom bar.
12. The system of claim 11 , wherein the load measuring device support assembly further comprises:
a first plate disposed at a first side of the front arm and the rear arm and a second plate disposed at a second side of the front arm and the rear arm, said front arm being pivotally affixed to the first plate and the second plate by a front pivoting axle and by a rear pivoting axle, said first side of the rear arm being permanently affixed to the first plate, said second side of the rear arm being permanently affixed to the second plate;
the S-type load cell being attachably mounted on a top surface of the front arm; and
a shaft attached to a front portion of the rear arm at one end, said shaft being threadably attached to the bottom bar of the S-type load cell.
13. The system of claim 10 , wherein the logic control unit of the closed-loop controller comprises a proportional calculator, a differential calculator and an integral calculator.
14. The system of claim 10 , wherein the process controller comprises:
an electric hub motor controller adapted for receiving, processing and transmitting signals, said electric hub motor controller being adapted for modulating a speed of the electric hub motor; and
a brake controller adapted for receiving, processing and transmitting signals, said brake controller being adapted for modulating braking of the trailer wheels.
15. The system of claim 10 , wherein the brake system comprises mechanical brakes and regenerative brakes.
16. The system of claim 10 , wherein the logic control unit comprises a PID controller.