Systems and methods are provided herein for operating a vehicle in a front dig mode. The front dig mode is engaged in response to determining that speed of the vehicle is below a speed threshold and determining that the amount that at least one of the front wheels of the vehicle is turned exceeds a turn threshold. While operating in the front dig mode, forward torque is provided to the front wheels of the vehicle. Further, resistance is applied to forward rotation of the inner back wheel of the vehicle. Yet further, forward torque is provided to the outer back wheel of the vehicle.

A working machine is provided, which includes a prime mover, a first traveling pump driven by power of the prime mover to supply operation fluid through a connector fluid tube, a traveling motor including first and second ports connected to the connector fluid tube, the traveling motor configured to be switched in a first speed and a second speed higher than the first speed, a first pressure detector to detect first traveling-pump pressure near the first port, a second pressure detector to detect second traveling-pump pressure near the second port, and a controller configured, with the traveling motor switched in the second speed, to automatically shift down the traveling motor from the second speed to the first speed, when a differential pressure between the first traveling-pump pressure and the second traveling-pump is equal to or more than a deceleration threshold.

A tractor has a base for supporting a motive power source, left and right driven wheels, and left and right transmissions for the respective left and right wheels. A handle structure is coupled to the base for grasping by an operator from behind the tractor. A drive system drives each of the left and right transmissions with motive power from the motive power source. A single lever hand control is provided for operation by a single hand of the operator for controlling both left and right transmissions seamlessly each between reverse speed through neutral and forward speed.

A tractor has a base for supporting a motive power source, left and right driven wheels, and left and right transmissions for the respective left and right wheels. A handle structure is coupled to the base for grasping by an operator from behind the tractor. A drive system drives each of the left and right transmissions with motive power from the motive power source. A single lever hand control is provided for operation by a single hand of the operator for controlling both left and right transmissions seamlessly each between reverse speed through neutral and forward speed.

A self-propelled harvesting machine includes a front harvesting attachment, a ground drive with first and second drive shafts offset relative to the front harvesting attachment, first and second track roller units to which first and second drive shafts are drivably connected and which extend on both sides of the harvesting machine and a rear axle having rear wheels that are steered via a steering mechanism provided in a rear region of the harvesting machine. The first and second drive shafts are driven by separate first and second hydraulic motors of a hydrostatic transmission. A displacement volume of each of the first and second hydraulic motors is changed depending on a steering movement transferred from the steering mechanism to the rear wheels, realizing an additional moment about a vertical axis of the harvesting machine simultaneously with the steering of the rear wheels.

A self-propelled harvesting machine includes a front harvesting attachment, a ground drive with first and second drive shafts offset relative to the front harvesting attachment, first and second track roller units to which first and second drive shafts are drivably connected and which extend on both sides of the harvesting machine and a rear axle having rear wheels that are steered via a steering mechanism provided in a rear region of the harvesting machine. The first and second drive shafts are driven by separate first and second hydraulic motors of a hydrostatic transmission. A displacement volume of each of the first and second hydraulic motors is changed depending on a steering movement transferred from the steering mechanism to the rear wheels, realizing an additional moment about a vertical axis of the harvesting machine simultaneously with the steering of the rear wheels.

A drive and control system for a lawn tractor includes a CAN-Bus network, a plurality of controllers, a pair of electric transaxles controlled by the plurality of controllers, and one or more steering and drive input devices coupled to respective sensor(s) for sensing user steering and drive inputs. The plurality of controllers communicate with one or more vehicle sensors via the CAN-Bus network. The plurality of controllers receive the user's steering and drive inputs and posts on the CAN-Bus network and generate drive signals to obtain the desired speed and direction of motion of the lawn tractor.

A drive and control system for a lawn tractor includes a CAN-Bus network, a plurality of controllers, a pair of electric transaxles controlled by the plurality of controllers, and one or more steering and drive input devices coupled to respective sensor(s) for sensing user steering and drive inputs. The plurality of controllers communicate with one or more vehicle sensors via the CAN-Bus network. The plurality of controllers receive the user's steering and drive inputs and posts on the CAN-Bus network and generate drive signals to obtain the desired speed and direction of motion of the lawn tractor.

A hydraulic system for controlling a pair of steerable caster wheels of an agricultural machine includes a fluidic tie rod fluid circuit interconnecting both a left side actuator and a right side actuator with a rear steering control valve in fluid communication, and forming a fluid tie rod between the left side actuator and the right side actuator. A tie rod control valve is disposed in the fluidic tie rod fluid circuit and is controllable between a first position allowing fluid communication through the fluidic tie rod fluid circuit to communicate fluid between the left side actuator, the right side actuator, and the rear steering control valve and a second position blocking fluid communication to the rear steering control valve while connecting the left side actuator and the right side actuator in fluid communication to increase stiffness of the fluid tie rod therebetween.

A zero turn radius vehicle with a single steered wheel is described. The vehicle may include a pair of power transfer mechanisms driving a pair of wheels, an operator control mechanism for controlling the steering, speed and direction of the vehicle and a controller in communication with the operator control mechanism. A steerable wheel is located adjacent the front of the vehicle frame, on a first side of the vehicle frame and an electric actuator is connected to the controller for steering the front steerable wheel. A second, non-steerable front caster wheel is located on a second side of the vehicle frame. The controller controls the pair of power transfer mechanisms and the electric actuator based on operator input to the operator control mechanism.