During dozing operation, the amount of earth (i.e., load factor) accumulated on the front face of a blade is automatically detected independently of the operator's perception and, based on the detection, the dozing operation is automatically shifted from digging to carrying. The load factor is calculated by obtaining a horizontal reaction force and a vertical reaction force exerted on the blade during digging and by calculating the ratio of the vertical reaction force to the horizontal reaction force. When the load factor reaches a specified value, the blade is automatically controlled to incline backward to hold the earth.

Dozing system for bulldozer

A loader (40) of the type controlled with an electronic digital controller (60) is disclosed herein. The loader may include conventional mechanical components. However, the hydraulic valve (54) is electronically controlled to provide improved motion control. In particular, the operator controls the loader with a two-axis joystick (64). When the joystick is moved left or right, the bucket (24) is rolled at a speed proportional to the rate of change of the joystick position and independent of the loader arms. When the joystick is moved forward or backwards, the loader arms (20) of the bucket are raised or lowered. When the joystick is only moved forward or backward with substantially no component of motion left or right, the controller rolls the bucket to maintain a substantially constant angle between the bucket (24) and the loader's frame (12). This constant attitude control decreases the operator workload and increases control accuracy. The controller provides velocity-based control over the loader arm and bucket motion, or flow-based control for improved stability and accuracy. The controller can monitor available flow and can then limit the commanded flows to the actuators to avoid exceeding the available flow.

Electronic control for a two-axis work implement

The present invention is directed to a computer based control system (50) for controlling a hydraulic (64) and electromechanical actuators (66) on a power machine (10). The computer based control (50) is configured to implement a number of features to enhance certain operational aspect of the power machine (10).

Features of main control computer for a power machine

A system for controlling a function of a machine system including an off-road work vehicle, a moveable device, and a positioning assembly including an actuator for moving the device in response to a control signal The system includes an operator-adjustable input device which generates an input signal, and a control circuit which generates the control signal for moving the moveable device in a first or a second manner depending upon the rate of change of the input signal The first manner is selected when the input signal changes slowly, and the second manner is selected when the input signal changes quickly The system may include a sensor for sensing a parameter of the machine system and a command device for generating a command signal A control signal is generated based at least upon the difference between the sensed parameter and command signals Also disclosed is a system for controlling the elevation of an implement carried or trailed by a work vehicle An implement positioning assembly includes an actuator for raising and lowering the implement in response to a control signal The control signal is generated in a first manner when the command signal changes slowly, and in a second manner when the command signal changes quickly An input device can also be used to override the normal rate of movement of an actuator with a slower value

Precision control of implement position/motion

Apparatus and method for automatically controlling the position of an earthmoving implement of an earthmoving machine in response to varying ground profiles

Site profile based control system and method for an earthmoving implement

An automatic lift and tip coordination system for use in connection with an off-highway vehicle having an implement causes an automatic adjustment to the implement lift actuators in response to an operator change in the implement tip angle so that the implement height remains constant.

Automatic lift and tip coordination control system and method of using same

An off-highway vehicle having an earth moving implement has a tilt function associated with the implement For example, a bulldozer has a tilt function associated with the bulldozer blade The vehicle has a processor adapted to receive a position signal from a position sensor associated with the tilt function of the implement The operator engages a switch to activate an automatic tilt function A selector switch is provided so that the operator can select between a plurality of pre-set blade angles The selector switch outputs a target position signal associated with a pre-set angle to the processor The processor automatically calculates a command signal for the tilt function based on the difference between the position signal and the target position signal The processor issues the command signal to the tilt function causing the tilt function to move the implement to the pre-set angle associated with the switch position

Automatic tip angle control

A system and method for guiding an off-highway truck along a roadway with respect to a trolley line determine a position of the off-highway truck on the roadway by sensing two or more roadside objects and uses the determined position of the off-highway truck and a known position of the trolley line relative to the two or more roadside objects to automatically determine a relative position of the off-highway truck under the trolley line. Based on the relative position of the off-highway truck under the trolley line, the off-highway truck is automatically steered to alter the position of the off-highway truck relative to the trolley line, e.g., to maintain an electrical power flow from the trolley line to the off-highway truck.

Laser Sensors For Trolley Guidance Signal

A system and method for automatically guiding an off-highway truck having a pantograph over a route having at least one trolley-powered section. While the off-highway truck is operated over the route by a human operator, its position and the state of the pantograph at each position are recorded to produce a recorded sequence. The recorded sequence is retrieved and the off-highway truck is automatically controlled to sequentially match each position and each pantograph state at the associated position.

Trolley driven machine record and playback automation

An off-road vehicle and in particular a bulldozer has a work shovel (55) that can be raised by the operation of one hydraulic cylinder (15) and can be tilted by the action of a second cylinder (20) to adjust the angle (theta). The actuators are controlled by an electronic unit that receives position and angle of tilt information. The controller operates to man a controlled position relative the ground surface. An input position is set by the user.

Ken L. Stratton

Papers

Automatic lift and tip coordination control system and method of using same

Automatic tip angle control

Laser Sensors For Trolley Guidance Signal

Trolley driven machine record and playback automation

Automatic stroke and angle coordination of bulldozer shovel