Enhanced driving control system for snowmobiles

A driving control system for enhancing steering control of a vehicle, the vehicle having a vehicle body and at least one ground engaging member connected to the vehicle body, the driving control system comprising:

• a steering system having a user operated steering element for adjusting an angle of the at least one ground engaging member relative to a longitudinal axis of the vehicle;
• an electrically actuated device coupled to the steering system for applying a torque to the steering system;
• a plurality of sensors to generate terrain condition data of the terrain and to generate operational data of the vehicle, wherein said plurality of sensors comprises a torque sensor to generate a portion of the operational data of the vehicle and at least one additional sensor;
• and
• at least one controller coupled to the electrically actuated device and the sensors, the at least one controller:
• selecting a terrain condition mode using the generated terrain condition data and the generated operational data, wherein the terrain condition mode is selected from a first mode, a second mode, and a third mode;
• determining a torque to apply to the steering system responsive to an angle and speed of rotation of the user operated steering element by using the selected terrain condition mode and the generated operational data;
• and
• operating the electrically actuated device to apply the torque to the steering system for providing enhanced steering control of the vehicle responsive to the angle and speed of rotation of the user operated steering element, with the torque being applied only by the electrically actuated device;
• the at least one additional sensor comprising a torque request sensor and an inertial navigation system module, a speedometer, a global positioning satellite module, a force sensor, and a side load torque sensor, and
• the controller selecting the terrain condition mode by:
• (a) using the torque request sensor to determine a relative throttle rate of a throttle mounted to the user operated steering element;
• (b) using the inertial navigation system module to determine a relative degree of vehicle roll of the vehicle;
• (c) using at least the torque sensor to determine a relative degree of steering damping gain for the vehicle;
• (d) using the speedometer or the global positioning satellite module, or both the speedometer and global positioning satellite module, to determine a relative degree of slip between the at least one ground engaging member and the terrain;
• (e) using the position sensor to determine a relative degree of load applied to a shock coupled to the at least one ground engaging member;
• (f) using the force sensor to determine a force applied to a seat coupled to the vehicle body from a user;
• (g) using the global positioning satellite module to determine a relative positioning of the vehicle on the terrain;
• (h) using the side load torque sensor to determine a relative degree of steering side load;
• (i) using the controller to select a preliminary terrain condition mode for each of the determined relative throttle rate and the determined relative degree of vehicle roll, the determined relative degree of steering damping gain for the vehicle, the determined relative degree of slip between the at least one ground engaging member and the terrain, the determined relative degree of load applied to the shock coupled to the at least one ground engaging member, the determined force applied to the seat coupled to the vehicle body from a user, the determined relative positioning of the vehicle on the terrain, and the determined relative degree of steering side load of parts (a)-(h), wherein the selected preliminary terrain condition mode is selected from a first preliminary terrain condition mode, a second preliminary terrain condition mode, and a third preliminary condition mode;
• and
• (j) selecting the terrain condition mode based on a comparison of the selected preliminary terrain condition modes of part (i).

A method for enhancing steering control of a vehicle, the vehicle having a vehicle body;

• at least one ground engaging member connected to the vehicle body;
• a steering system having a user operated steering element for adjusting an angle of the at least one ground engaging member relative to a longitudinal axis of the vehicle;
• and a plurality of sensors to generate terrain condition data of a terrain and to generate operational data of the vehicle, wherein said plurality of sensors comprises a torque sensor to generate a portion of the operational data of the vehicle and at least one additional sensor comprising a torque request sensor and an inertial navigation system module;
• the method comprising the steps of:
• determining a terrain condition mode based on the generated terrain condition data and the generated operational data, wherein the terrain condition mode is selected from a first mode, a second mode, and a third mode, by:
• (a) determining a relative throttle rate of a throttle mounted to the user operated steering element using the torque request sensor;
• (b) determining a relative degree of vehicle roll of the vehicle using the inertial navigation system module;
• (c) determining a relative degree of steering damping gain for the vehicle using at least the torque sensor;
• (d) selecting a preliminary terrain condition mode for each of the determined relative throttle rate and the determined relative degree of vehicle roll, and the determined relative degree of steering damping gain of parts (a)-(c), wherein the selected preliminary terrain condition mode is selected from a first preliminary terrain condition mode, a second preliminary terrain condition mode, and a third preliminary condition mode;
• (e) comparing the selected preliminary terrain condition modes for each of the determined relative throttle rate, the determined relative degree of vehicle roll, and the determined relative degree of steering damping gain for the vehicle in part (d);
• and
• (f) selecting the terrain condition mode from the comparison of the selected preliminary terrain condition modes in part (e);
• receiving rotational movement of the user operated steering element;
• determining a torque to apply to the steering system responsive to an angle and speed of the received rotational movement of the user operated steering element by using the selected terrain condition mode and the generated operational data;
• and
• applying the torque to the steering system for providing enhanced steering control of the vehicle responsive to the angle and speed of rotational movement of the user operated steering element, with the torque being applied only by an electrically actuated device of the vehicle.