Lawn tractor with electronic drive and control system
A drive and control system for a lawn tractor includes one or more sensors configured to detect an operational parameter of an aspect of the vehicle, and one or more controllers for controlling one or more components of the vehicle and for receiving data output from the one or more sensors. The controller communicates with the one or more sensors and one or more vehicle modules configured to control one or more vehicle components via a CAN Bus network. The controller may be coupled to an IMU mounted on the vehicle for dynamically controlling the vehicle on sloped terrain, for example. The controller may be accessible from a remote device over a wireless network for communicating setup, diagnostic, and performance data to and from the vehicle.
1. A drive and control system for a lawn tractor, comprising:
a CAN-Bus network operable to communicate signals to and from one or more components of the lawn tractor;
a vehicle control module comprising a processor and memory, the vehicle control module being operable to receive a plurality of analog input signals and a plurality of digital input signals from one or more components of the lawn tractor and to transmit digital output signals via the CAN-Bus network to one or more components of the lawn tractor;
first and second drive systems comprising:
(a) first and second hydrostatic transaxles comprising first and second output axles, respectively;
(b) a first electric actuator having a first electronic drive module connected to the first hydrostatic transaxle for controlling an output speed and direction of motion of the first output axle, and a second electric actuator having a second electronic drive module connected to the second hydrostatic transaxle for controlling an output speed and direction of motion of the second output axle;
a steering and drive input device for receiving user input regarding desired speed and direction of motion of the lawn tractor; and
a steering and drive sensor module connected to the steering and drive input device for detecting position, speed and direction of motion of the steering and drive input device and operable to post on the CAN-Bus network a steering and drive input command corresponding to the position, speed and direction of motion of the steering and drive input device;
wherein the vehicle control module is configured to process the steering and drive input command and post on the CAN-Bus network a steering and drive output command corresponding to the desired speed and direction of motion of the lawn tractor, and
wherein the first and second electronic drive modules are configured to process and convert the steering and drive output command to appropriate first and second actuator commands to drive the first and second electric actuators to obtain the desired speed and direction of motion of the lawn tractor.
2. The drive and control system of claim 1 , wherein the first and second electronic drive modules are configured to continuously compare actual first and second electric actuator positions to the position, speed and direction of motion posted by the vehicle control module and update the first and second actuator positions to approximate the position, speed and direction of motion detected by the vehicle control module.
3. The drive and control system of claim 1 , wherein the first and second electronic drive modules are configured to use a motion profile algorithm based on tunable parameters stored in memory on each of the first and second electronic drive modules to individually drive the first and second electric actuators.
4. The drive and control system of claim 3 , wherein the tunable parameters are defined according to a plurality of user access levels, wherein each of the user access levels comprise one or more different accessible tunable parameters than the other of the user access levels.
5. The drive and control system of claim 1 , wherein the vehicle control module includes an interface for receiving the plurality of analog input signals from a plurality of analog input devices.
6. The drive and control system of claim 5 , wherein the plurality of analog input devices includes a seat occupancy sensor configured to detect presence of weight on a seat of the lawn tractor, wherein the seat occupancy sensor is configured to post on the CAN-Bus network an activation signal corresponding to the presence of weight on a user's seat mounted on the lawn tractor and wherein the vehicle control module is configured to respond to the activation signal.
7. The drive and control system of claim 5 , wherein the plurality of analog input devices includes a PTO engagement sensor configured to detect an “on” or “off” engagement status of a PTO device, wherein the PTO engagement sensor is configured to post on the CAN-Bus network an “on” or “off” engagement signal corresponding to the “on” or “off” engagement status of the PTO device and wherein the vehicle control module is configured to respond to the “on” or “off” engagement signal.
8. The drive and control system of claim 5 , wherein the plurality of analog input devices includes a parking brake engagement sensor configured to detect an “on” or “off” engagement status of a parking brake, wherein the parking brake engagement sensor is configured to post on the CAN-Bus network an “on” or “off” engagement signal corresponding to the “on” or “off” engagement status of the parking brake and wherein the vehicle control module is configured to respond to the “on” or “off” engagement signal.
9. The drive and control system of claim 5 , wherein the plurality of analog input devices includes a key switch from which the vehicle control module obtains electrical power, wherein the vehicle control module is configured to receive electrical power when the key switch is in an “on” position and to cease receiving electrical power when the key switch is in an “off” position, wherein when the key switch is in the “on” position, the vehicle control module provides electrical power to energize the CAN-Bus network.
10. The drive and control system of claim 5 , including a user interface module comprising a display screen connected to the CAN-Bus network and configured to display lawn tractor status information messages generated by the vehicle control module and posted to the CAN-Bus network.
11. The drive and control system of claim 10 , wherein the display screen is a touch screen configured to receive user input that is posted on the CAN-Bus network.
12. The drive and control system of claim 1 , including a stability control module coupled to the vehicle control module, the stability control module configured to provide vehicle straight line tracking, wheel slip and traction control, hillside stability, and rollover protection during operation of the lawn tractor.
13. The drive and control system of claim 12 , wherein the stability control module includes an inertial measurement unit module configured to post on the CAN-Bus network a digital attitude and heading reference signal corresponding to detected attitude and heading motion of the lawn tractor for use by the vehicle control module.
14. The drive and control system of claim 13 , wherein the digital attitude and heading reference signal is obtained by a fusion of output signals from a multi-axis accelerometer, a multi-axis gyroscope, and a multi-axis magnetometer.
15. The drive and control system of claim 14 , wherein the fusion of output signals results in a vector in 3 dimensions.
16. The drive and control system of claim 1 , wherein the vehicle control module is configured to send, via the CAN-Bus network, a control signal to the first and second electronic drive modules to reduce the speed of the lawn tractor to a predetermined speed irrespective of the detected position, speed and direction of motion of the steering and drive input device.
17. A drive and control system for a lawn tractor, comprising:
a CAN-Bus network operable to communicate signals to and from one or more components of the lawn tractor;
a vehicle control module comprising a processor and memory, the vehicle control module being operable to receive a plurality of input signals from one or more components of the lawn tractor and to transmit output signals via the CAN-Bus network to one or more components of the lawn tractor; and
first and second drive systems comprising first and second electric actuators with first and second electronic drive modules, respectively, for controlling a speed and direction of motion of the lawn tractor,
wherein the vehicle control module is configured to process a steering and drive input command and post on the CAN-Bus network a steering and drive output command corresponding to a desired speed and direction of motion of the lawn tractor, and
wherein the first and second electronic drive modules are configured to process the steering and drive output command to generate appropriate first and second actuator commands to drive the first and second electric actuators to obtain the desired speed and direction of motion of the lawn tractor.
18. The drive and control system of claim 17 , wherein the first and second electronic drive modules are configured to continuously update a respective position of each of the first and second electric actuators based on updated steering and drive output commands posted on the CAN-Bus network by the vehicle control module.
19. The drive and control system of claim 17 , wherein the first and second electronic drive modules are configured to use a motion profile algorithm based on tunable parameters stored in memory on each of the first and second electronic drive modules to individually drive the first and second electric actuators.
20. The drive and control system of claim 19 , wherein the tunable parameters are defined according to a plurality of user access levels, wherein each of the user access levels comprise one or more different accessible tunable parameters than the other of the user access levels.