Control system for an adverse terrain vehicle

An adverse terrain vehicle having a frame with at least three wheel members rotatably mounted on each side thereof comprising:

• at least two variable displacement hydraulic motors mounted on the frame each for driving at least one wheel member on one side of the vehicle independently of the wheel members on the opposing side of the vehicle;
• at least two variable displacement hydraulic pumps mounted on the vehicle for supplying pressurized hydraulic fluid to the hydraulic motor on one side of the vehicle independently of the hydraulic motor on the opposing side of the vehicle;
• at least one prime mover for driving the hydraulic pumps;
• overload sensing means for sensing a decrease in the power output of the vehicle below a selected power output;
• overload protection means responsive to the overload sensing means for increasing the displacement of the hydraulic motors and for decreasing the displacement of the hydraulic pumps, thereby increasing the power output capacity of the vehicle;
• steering means for directing movement of the vehicle along a selected path, including means for adjusting the speed of the hydraulic motor on at least one side of the frame to effect turning of the vehicle;
• braking means response to the steering means for selectively applying braking forces to the wheel members on opposite sides of the vehicle to reduce the velocity of the vehicle along the selected path and simultaneously turning the vehicle during braking as determined by the steering means;
• wheel member positioning means for selectively verticially positioning the wheel members on each side of the vehicle relative to the frame;
• means for sensing the speed of the hydraulic motor on each side fo the vehicle;
• motor control means responsive to the motor speed sensing means for varying the displacement of the hydraulic motor on each side of the vehicle as the motor speed exceeds a predetermined value and as the motor speed drops below a lower predetermined value;
• means responsive to the steering means for adjusting the displacement of at least one of the hydraulic pumps to effect turning of the vehicle when the vehicle is slowing or coasting;
• wherein the braking means applies a braking force to one or more of the wheel members on each side of the vehicle in proportion to the degree of braking selected within a predetermined range of braking forces;
• wherein the braking means reduced the braking force applied to the wheel members on the outside of a selected turn during braking in response to the steering means thereby directing the path of vehicle travel;
• and
• wherein the braking means reduces the braking force applied to the wheel members on the outside of a selected turn by pulsating the braking force applied to the wheel members on the outside of the selected turn.

An adverse terrain vehicle having a frame with at least three wheel members rotatably mounted on each side thereof comprising:

• at least two variable displacement hydraulic motors mounted on the frame each for driving at least one wheel member on one side of the vehicle independently of the wheel members on the opposing side of the vehicle;
• at least two variable displacement hydraulic pumps mounted on the vehicle for supplying pressurized hydraulic fluid to the hydraulic motor on one side of the vehicle independently of the hydraulic motor on the opposing side of the vehicle;
• at least one prime move for driving the hydraulic pumps;
• overload sensing means for sensing a decrease in the power output of the vehicle below a selected power output;
• overload protection means responsive to the overload sensing means for increasing the displacement of the hydraulic motors and for decreasing the displacement of the hydraulic pumps, thereby increasing the power output capacity of the vehicle;
• steering means for directing movement of the vehicle along a selected path, including means for adjusting the speed of the hydraulic motor on at least one side of the frame to effect turning of the vehicle;
• braking means response to the steering means for selectively applying braking forces to the wheel members on opposite sides of the vehicle to reduce the velocity of the vehicle along the selected path and simultaneously turning the vehicle during braking as determined by the steering means;
• wheel member positioning means for selectively vertically positioning the wheel members on each side of the vehicle relative to the frame;
• means for sensing the speed of the hydraulic motor on each side fo the vehicle;
• motor control means responsive to the motor speed sensing means for varying the displacement of the hydraulic motor on each side of the vehicle as the motor speed exceeds a predetermined value and as the motor speed drops below a lower predetermined value;
• means responsive to the steering means for adjusting the displacement of at least one of the hydraulic pumps to effect turning of the vehicle when the vehicle is slowing or coasting;
• and
• wherein the wheel member positioning means includes one or more hydraulic cylinders for extending and retracting each wheel member, wherein the wheel member positioning means further includes means for applying substantially uniform pulses of hydraulic fluid to each cylinder to position the wheel member associated therewith, and wherein the placement of each cylinder is determined by the number of pulses of hydraulic fluid applied thereto.

An adverse terrain vehicle having a frame with at least two wheel members rotatably mounted on each side thereof comprising:

• at least two variable displacement hydraulic motors mounted on the frame each for driving at least one wheel member on one side of the vehicle independently of the wheel members on the opposing side of the vehicle;
• at least two variable displacement hydraulic pumps mounted on the vehicle for supplying pressurized hydraulic fluid to the hydraulic motor on one side of the vehicle independently of the hydraulic motor on the opposing side of the vehicle;
• at least one prime mover for driving the hydraulic pumps;
• overload sensing means for sensing a decrease in the power output of the vehicle below a selected power output;
• overload protection means responsive to the overload sensing means for increasing the power output capacity of the vehicle by varying the displacement of at least one of the pumps and motors;
• and
• wherein the overload protection means first increases the displacement of the hydraulic motors and thereafter decreases the displacement of the hydraulic pumps in response to the overload sensing means.

An adverse terrain vehicle having a frame with at least two wheel members rotatably mounted on each side thereof comprising:

• at least two variable displacement hydraulic motors mounted on the frame each for driving at least one wheel member on one side of the vehicle independently of the wheel members on the opposing side of the vehicle;
• at least two variable displacement hydraulic pumps mounted on the vehicle for supplying pressurized hydraulic fluid to the hydraulic motor on one side of the vehicle independently of the hydraulic motor on the opposing side of the vehicle;
• at least one prime mover for driving the hydraulic pumps;
• overload sensing means for sensing a decrease in the power output of the vehicle below a selected power output;
• overload protection means responsive to the overload sensing means for increasing the power output capacity of the vehicle by varying the displacement of at least one of the pumps and motors;
• and
• pump and motor control means for varying the displacement of the pumps and motors in response to variation of the selected power output, wherein the pump and motor control means first increases the displacement of the pumps and then decreases the displacement of the motors as the selected power output increases from a predetermined minimum value to a predetermined maximum value.

An adverse terrain vehicle having a frame with at least two wheel members rotatably mounted on each side thereof comprising:

• at least two motor means mounted on the frame each for driving at least one wheel member on one side of the vehicle independently of the wheel members on the opposing side of the vehicle;
• steering means for directing movement of the vehicle along a selected path, including means for adjusting the speed of the motor means on at least one side of the frame to effect turning of the vehicle;
• braking means responsive to the steering means for selectively applying braking forces to the wheel members on opposite sides of the vehicle to reduce the velocity of the vehicle along the selected path and simultaneously turning the vehicle during braking as determined by the steering means, wherein the braking means applies a braking force to one or more of the wheel members on each side of the vehicle in proportion to the degree of braking selected within a predetermined range of braking forces;
• wherein the braking means reduces the braking force applied to the wheel members on the outside of a selected turn during braking in response to the steering means thereby directing the path of vehicle travel;
• and
• wherein the braking means reduces the braking force applied to the wheel members on the outside of a selected turn by pulsating the braking force applied to the wheel members on the outside of the selected turn.

An adverse terrain vehicle having a frame with at least three wheel members rotatably mounted on each side thereof comprising:

• at least two motor means mounted on the frame each for driving at least one wheel member on one side of the vehicle independently of the wheel members on the opposing side of the vehicle;
• steering means for directing movement of the vehicle along a selected path, including means for adjusting the speed of the motor means on at least one side of the frame to effect turning of the vehicle;
• and
• wheel member positioning means for selectively vertically positioning the wheel members on each side of the vehicle relative to the frame, including one or more hydraulic cylinders for extending and retracting each wheel member, wherein the wheel member positioning means further includes means for applying substantially uniform pulses of hydraulic fluid to each cylinder to position the wheel member associated therewith, and wherein the placement of each cylinder is determined by the number of pulses of hydraulic fluid applied thereto.