Abstract: A control system for determining a position of an implement arm having a work implement is disclosed. The implement arm includes mating components connected by at least one joint. The control system includes at least one position sensor operably associated with the implement arm and configured to sense positional aspects of the implement arm. It also includes at least one load sensor operably associated with the implement arm, and configured to sense the direction of loads applied to the at least one joint. A controller is adapted to calculate a position of the implement arm based on signals received from the at least one position and load sensor. The calculated position takes into account shifting of the implement arm caused by clearances existing at the at least one joint between the mating components of the implement arm.

Abstract: A control system for determining a position of an implement arm having a work implement is disclosed. The implement arm includes mating components. The control system includes at least one sensor operably associated with the implement arm and configured to sense positional aspects of the implement arm. A controller is adapted to calculate a position of the implement arm based on signals received from the at least one sensor. The calculated position takes into account shifting of the implement arm caused by clearances existing between the mating components of the implement arm.

Abstract: A system and method for estimating the position of a mechanical linkage is disclosed. An estimated position of a mechanical linkage is set to an initial position. The movement of the mechanical linkage is controlled based on a signal from an input device. The estimated position of the mechanical linkage is updated based upon the movement of the mechanical linkage. A determination is made when the estimated position of the mechanical linkage substantially corresponds to an actual position of the mechanical linkage.

Abstract: A system to control a piece of construction equipment or other piece of heavy equipment at a remote location via a data network in which a user provides movement instructions via a graphical user interface at a user PC to a programmable controller interfaced to the data network and the hydraulic movement systems of the heavy equipment. The graphical user interface includes a visual representation portion and a user control portion. A visual representation of the moveable elements of the heavy equipment is provided to the user via the graphical user interface, and the user inputs movement instructions via the user control portion of the graphical user interface.

Abstract: An automatically operated shovel, which includes a power shovel and an automatic operation controller 50 for making the power shovel reproduce a series of taught operations ranging from digging to dumping, is characterized in that the automatic operation controller is provided with a positioning determinator for determining whether or not the power shovel has reached within a taught position range predetermined based on corresponding one of positioning accuracies set for individual taught positions of said power shovel, and, when the power shovel is determined to have reached within the predetermined taught position range, the automatic operation controller outputs a next taught position as a target position.

Abstract: A system having a monitoring function in addition to a control function is able to suppress an increase in the amount of data communication and the communication frequency via a common communication line, and is flexibly adaptable for the addition of a new function without causing mutual interference between control data and monitor data. In particular, a hydraulic excavator 1 includes a first control unit 17 for a prime mover 14, a second control unit 23 for a hydraulic pump 18, a third control unit 33 for control valves 24, 25 and 26, and first and second monitor units 45, 46. A first common communication line 39 for control and a second common communication line 40 for monitoring are further provided as common buses for data communication.

Abstract: A method and apparatus for updating a machine database. The database includes data representing the desired and actual terrain of a work site. Additional data represents portions of the work site which have been further worked. An indicator detects the machine's current work function and updates the data in the database based on the current work function.

Abstract: A snow plow system for use with a skid steer loader includes a V-plow blade that is repositionable by a hydraulic actuator operated by pressurized hydraulic fluid supplied to the actuator from the auxiliary hydraulic output of the skid steer loader. A normally open valve diverts hydraulic fluid away from the actuator whenever the plow blade is not being repositioned, enabling the auxiliary hydraulic system to be maintained actuated. The valve is operated to a closed condition by a wireless remote control receiver which receives coded radio frequency signals transmitted by a wireless, portable, battery-powered transmitter locatable within or outside of a cab of the vehicle, or by a voice-actuated control. A mounting panel of the snow plow system includes an anti-slip surface, providing footing for an operator upon entering or exiting the cab of the vehicle.

Abstract: The present invention is a control system for controlling movement of a work implement from a dig location to a dump location. The work implement has at least four degrees of freedom defined by a swing joint angle &thgr;swing, a boom joint angle &thgr;boom, a stick joint angle &thgr;stick, and a bucket joint angle &thgr;bucket. In one embodiment, the control system comprises a central processing unit and a memory device. The control system further comprises an initialization module stored on the memory device and adapted to determine specified initial and final joint angles for an initial cycle of the work implement indicative of the specified dig and dump locations, respectively. The control system further comprises a hydraulic valve connected to the central processing unit and to the work implement. The control system further comprises a fuzzy control module stored on the memory device.

Abstract: A system and method for updating parameter data available to a machine control system. A work machine having an implement attached thereto includes a machine control system for controlling the machine and the implement and for providing additional functionality, such as mapping and payload systems, to the machine. The machine control system is configurable for operation of a variety of work implements. Data associated with the attached work implement is retrieved from a remote system and utilized to adjust the machine control system to accommodate the attached implement.

Abstract: A control system for orienting a swing axis of a work machine is disclosed. The work machine includes a swing frame and a frame structure, and the control system includes an operator interface configured to receive operator inputs, wherein the operator inputs represent a desired orientation of the swing axis of the swing frame. The control system also includes a sensor assembly configured to determine an actual orientation of the swing axis of the swing frame and a controller configured to compare the desired orientation to the actual orientation of the swing axis to determine a swing angle. The controller is adapted to output the swing angle. The swing axis may be adjusted by adjusting the work machine frame or by adjusting a frame assembly independent of the work machine frame.

Abstract: A skid steer vehicle has a sprung suspension system including four wheels mounted on four swing arms that are pivotally coupled to the chassis of the vehicle. An electronic controller is connected both to position sensors coupled to the swing arms to sense the position of the swing arms and wheels with respect to the chassis and also to hydraulic cylinders that control the position of the swing arms and wheels. The electronic controller determines the average position of each suspension and controls the flow of fluid to the cylinders to keep the swing arms and wheels at their proper target height when vehicle load changes.

Abstract: A skid steer vehicle has a sprung suspension system including four wheels mounted on four swing arms that are pivotally coupled to the chassis of the vehicle. An electronic controller is connected both to position sensors coupled to the swing arms to sense the position of the swing arms and wheels with respect to the chassis and also to hydraulic cylinders that control the position of the swing arms and wheels. The electronic controller determines the average position of each suspension and controls the flow of fluid to the cylinders to keep the swing arms and wheels at their proper target height when vehicle load changes.

Abstract: A method and apparatus for determining a force of a work tool as the work tool contacts a surface. The method and apparatus includes determining at least one non-contact force exerted on the work tool, determining a calibration factor as a function of the at least one non-contact force, determining a contact being made between the work tool and the surface, and determining the contact force of the work tool with the surface as a function of the contact being made and the calibration factor.

Abstract: A diagnostic and control unit allows a field technician to unlock and monitor the operation of a power machine, perform diagnostics on the power machine or modify the operating parameters of the power machine without bringing the power machine to a service station or back to the factory. The diagnostic and control unit illustratively includes a remote start and control interface, and a controller. The remote start and control interface receives inputs for unlocking the operation of one or more the hydraulic functions on the power machine.

Abstract: A method for determining a position and a heading of a work machine having a work implement controllably attached. The method includes the steps of positioning the work machine at a desired work location, determining an initial position and heading of the work machine in site coordinates, determining a position of the work implement relative to the work machine, positioning the work implement at a desired reference point, determining the position of the work implement at the reference point in site coordinates, periodically positioning the work implement at the reference point during work operations, and determining a new position and heading of the work machine as a function of the position of the work implement relative to the work machine.

Abstract: In accordance with the present invention, a system to organize and coordinate components associated with earthmoving machinery capable of performing excavating and loading tasks autonomously is disclosed. The system comprises an earthmoving machine equipped with a scanning sensor system operable to provide data regarding regions within an earthmoving environment including an excavation region and a loading region and a planning and control module operable to receive data from the scanning sensor system to plan a task associated with the control of the earthmoving machine while concurrently performing another task associated with control of the earthmoving machine. Any number and type of sensor systems, such as a laser rangefinder or a radar rangefinder, may be incorporated in the system depending on requirements and the capabilities of the system.

Abstract: A hydraulic excavator 1 comprises a prime mover 14, an excavating device 7, a hydraulic pump 18 rotationally driven by the prime mover, actuators 11, 12, 13 for driving the working device, and control levers 27, 27, 29 for operating control valves 24, 25, 26 for controlling a hydraulic fluid supplied from the hydraulic pump to the actuators. Control units 17, 23, 33, 37 and a display unit 38 are provided on the hydraulic excavator, the control units being associated with the prime mover, the excavating device, the hydraulic pump and the control levers. The control units and the display unit are interconnected via a common communication line 39 to transmit and receive data among them. The control units each include minimum processing means capable of performing computation by using an initial value and executing least necessary processing by itself when no data is transmitted via the communication line.

Abstract: A method and system for altering operating behavior of a sub-system component of a machine to suit a user's preference includes a database for storing a plurality of parameters associated with the operating behavior of the sub-system component. The parameters have sets of values associated therewith wherein each set of values define one of a plurality of acceptable operating behaviors for the sub-system component. A sub-system controller receives a selection signal from the operator via a user interface selecting one of the set of values of the parameters according to his/her preference. The sub-system controller then controls the sub-system component based on the selected set of values for the parameters.

Abstract: An automatically operated shovel has a shovel and an automatic operation controller arranged on the shovel to store by a teaching operation plural working positions of the shovel, which comprises at least a digging position, and also to cause by a reproduction operation the shovel to repeatedly perform a series of reproduction operations on the basis of the stored plural working positions. The automatic operation controller is provided with servo control means for outputting, as a servo control quantity, a sum of a compliance control quantity and a pressure control quantity. The compliance control quantity is obtained by multiplying with a stiffness gain a difference between a target position of each operational element of the shovel, the target position comprising angle information indicative of an operational target of the operational element, and a current position of the operational element, the current position comprising current angle information on the operational element.

Abstract: A tractor includes various actuators or functions, such as a powershift transmission, a hitch and hitch control system, a PTO, a plurality of selective control valves, etc., all controlled by one or more control units in response to sensed parameters and operator manipulated control devices, such as switches, knobs and levers. A function management system includes a programmed control unit which has a learn/save mode which is operable while the vehicle is moving. During the learn/save mode the operator performs a sequence of manual manipulations of the operator control devices, and the control unit records and then stores information pertaining to the sequence of operations, together with information pertaining to the distances traveled by the tractor between operations.

Abstract: The present method and apparatus provide a control system on a machine including an electronic controller for controlling operation of at least one subsystem, an internal data storage device containing data readable by the controller representative of an allowable range for controlling an operating parameter for the subsystem, and a data interface operable for allowing the controller to access data contained in an external data storage device. The present method and apparatus additionally provide an external data storage device containing data accessible by the controller representative of at least one preferred value for controlling the operating parameter.

Abstract: An apparatus for controlling the torque associated with a power train of a machine having a work implement is disclosed. A plurality of position sensors sense the position associated with the work implement and responsively produce respective position signals. A controller modifies the desired engine speed in response to the angular position of the work implement and regulates the speed of the engine at the modified desired engine speed to control the power train torque.

Abstract: An apparatus for determining a condition indicative of a level of difficulty of excavation of a material engaged by a work machine having a work implement. A controller receives a first signal during a dig pass of the work machine, and determines a material condition indicative of a level of difficulty of excavation during the dig pass as a function of the first signal, and transmits an output signal during the dig pass as a function of the material condition.

Abstract: A wheel loader, having a higher acceleration and an energy-saving performance, as well as a higher traveling and working efficiency, includes: a traveling system, having an engine (1) as a driving power source; and a hydraulic working system, operated by receiving pressurized oil from a hydraulic pump (81, 82) having the engine (1) as a driving power source. The hydraulic pump can be a variable displacement hydraulic pump (81) or the combination of a fixed displacement pump (82) and an unloader valve (821). The displacement volume (V) of the variable displacement hydraulic pump (81) can be changed from a maximum (Vmax) to a minimum (Vmin) when the hydraulic working system is changed to be in a neutral (non-operating) condition (Wo). The useful output of the hydraulic pump (81,82) can be changed from a maximum (Vmax) to a minimum (Vmin) when a vehicle speed is greater than a specified vehicle speed, or the speed gear is changed from a low side speed gear to a high side speed gear.

Abstract: In one embodiment of the present invention, a planning apparatus and method for earthmoving operations with a front-end loader, such as loading a bucket with material and unloading the material in a receptacle, is disclosed including multi-level processing for planning the operation. One of the processing levels is a coarse-level planner that uses geometry of the site and heuristics specified by expert operators to find an optimal area from which to remove material. The next level involves searching the area for an exact starting location. This is accomplished by choosing among candidate excavations for the site with the optimum performance criteria including maximum amount of material protruding from the pile, minimum side loading of the bucket, and minimum distance from the loading receptacle.

Abstract: A hydraulic drive type working vehicle, with speedy responsiveness in an excavating operation, includes: a pouring changeover valve (10), which is switchable between (a) a pouring position, wherein pressurized oil of a travel hydraulic circuit (5) is poured into a working machine hydraulic circuit (8), and (b) a shutoff position, wherein the travel hydraulic circuit (5) and the working machine hydraulic circuit (8) are isolated from each other; a first changeover valve (16), which is switchable from its shutoff position to its communicating position when the oil pressure of the travel hydraulic circuit (5) exceeds a predetermined oil pressure; a pouring command switch (14); and a second changeover valve (17), which is connected in series with the first changeover valve (16) and which is switchable from its shutoff position to its communicating position upon receipt of a pouring command from the pouring command switch (14); and wherein the pouring changeover valve (10) is switchable to the pouring position whe

Abstract: In one aspect of the present invention, a method for determining and displaying a correlated position of a truck as it is being loaded by an earth moving machine is provided. The method includes the steps of receiving a loading event signal and then determining the correlated position of the truck in response to the loading event signal. The correlated position of the truck is then displayed relative to the land size.In an alternative embodiment, a method for determining and displaying productivity information regarding material excavated by an earth moving machine and loaded into a truck is provided. The method includes the steps of determining the bucket load material type of the material loaded in the bucket. Productivity information is then displayed at a remote location in response to the bucket load material type.

Abstract: In one embodiment of the present invention, a planning system and method for earthmoving operations such as digging a foundation or leveling a mound of soil is disclosed including three different levels of processing for planning the excavation. One of the processing levels is a coarse-level planner that uses geometry of the site and the goal configuration of the terrain to divide the excavation area into a grid-like pattern of smaller excavation regions and to determine the boundaries and sequence of excavation for each region. The next level is a refined planner wherein each excavation region is, in order of the excavation sequence provided by the coarse planner, searched for the optimum excavation that can be executed. This is accomplished by choosing candidate excavations that meet geometric constraints of the machine and that are approximately within the boundaries of the region being excavated.

Abstract: A control apparatus of a construction machine, such as hydraulic excavator, includes arms supported on the construction machine body side, a working member supported by the arms and hydraulic cylinder actuators for operating the arms and the working member, for realizing a smooth variation of an instruction value to the hydraulic cylinder actuators even if the working member is operated suddenly upon starting an operation. In the control apparatus, the arm and working members are operated by driving a control member, a target moving velocity of the working member is set so that the characteristics of the arms and working member upon starting an operation and upon ending an operation as time differentiated are regarded as those before time differentiated, and the actuators are controlled based on the target moving velocity information so that the working member is operated at the target moving velocity.

Abstract: An arrangement for controlling at least one adjusting element of a work vehicle has a control unit electrically connectable with adjusting elements, at least one operating element electrically connected with the control unit and operative for actuating a control function processed in the control unit, the control unit being provided with a structure which, in dependence on a sequence provided by an operator, supply adjusting functions as adjusting signals to the corresponding adjusting elements.

Abstract: In one embodiment of the present invention, a motion planning algorithm is used to control an autonomous machine. The motion planning algorithm consists of a template or script which captures the general trends of the motion, while parameters in the script are filled in with the kinematic details for a specific machine and set of movements. A learning algorithm computes the script parameters by using feedback of how the machine performed during the preceding cycle with the current parameter set, and adjusting the parameters to improve the machine's performance during succeeding work cycles. The new parameters are evaluated by the learning algorithm using a predictive function approximator to test various performance criteria such as the time required to perform a task and the accuracy with which the task was performed.

Abstract: An electrohydraulic control system for loading a bucket of an earthmoving machine includes sensors for sensing when the machine is crowding a pile of material to be loaded. A command signal generator monitors the sensed "crowd" parameters to trigger one of a learning or playback mode for hydraulic cylinder command signals when the parameter indicates pile contact.

Abstract: An apparatus for limiting the control of a work implement is disclosed. The implement is connected to a work machine and is moveable in response to operation of a hydraulic cylinder. The apparatus includes an operator controlled joystick. A joystick position sensor senses the position of the joystick and responsively generates an operator command signal. An implement position sensor senses the position of the work implement and responsively produces an implement position signal. A microprocessor based controller receives the implement position and operator command signals, modifies the operator command signal, and produces an electrical valve signal in response to the modified operator command signal. An electrohydraulic valve receives the electrical valve signal, and controllably provides hydraulic fluid flow to the hydraulic cylinder in response to a magnitude of the electrical valve signal.

Abstract: A working machine control device for construction machinery provided with a plurality of joined working arms, an attachment mounted to the leading end of the working arms and a plurality of actuators for driving the working arms and the attachment, includes a function to adjust a pushing force between the attachment and a working plane by automatically controlling at least one of the actuators. The control device also includes a load detecting unit for detecting a load applied from the working plane to the attachment, working machine posture detecting devices for detecting postures of the working arms and the attachment and a computing unit for computing the pushing force between the attachment and the working plane on the basis of output values from the load detecting unit and the working machine posture detecting devices. The computing unit outputs a component of the pushing force in a direction perpendicular to the working plane.

Abstract: An area where a front device (1A) is allowed to move is set beforehand and the operation of the front device is controlled so that the front device will not go out of the set area. For this control process, an arm cylinder speed calculating portion (9d) of a control unit (9) estimates an arm cylinder speed for use in control by taking the sum of a low-frequency component of an arm cylinder speed which is derived through coordinate transformation and differentiation of an arm rotational angle detected by an angle sensor (8b), and a high-frequency component of an arm cylinder speed which is derived from a command value applied from a control lever unit (14b) to a flow control valve (15b) for an arm and a flow rate characteristic of the flow control valve (15b). The control unit controls the operation of the front device with the estimated operating speed.

Abstract: The invention is a method for monitoring a work cycle of a earth moving machine on a land site. The method includes the steps of determining a direction of motion of the earth moving machine as being either a forward or a reverse direction of motion, determining a change in the direction of motion to an opposite direction of motion, determining a location of the earth moving machine on the land site where the change in direction of motion occurs, determining a condition of the land site at the location, and determining a work cycle of the earth moving machine in response to the condition.

Abstract: A method is disclosed for controlling the cutting depth and angle of an excavator bucket to excavate a surface to a desired contour. The method includes the steps of: (1) inputting data to a machine control system to define a desired contour of the excavated surface; (2) positioning the excavator bucket close to the desired contour; (3) enabling automatic control; and (4) automatically controlling movement of the excavator bucket only when the position of the excavator bucket is within a predetermined distance or angle of the desired contour. The method is used to automatically control the excavation to a desired depth if the bucket is within a predetermined distance of a desired depth. The method is also used to automatically control the angular orientation of bucket if the slope of the bucket is within a predetermined angle of a desired slope.

Abstract: A method of using a touch screen control panel to input and display data to control excavation by an excavator includes the steps of: (1) providing a display panel with a touch-sensitive screen at a position accessible to an operator; (2) inputting data by touching the display panel to define a desired contour of the excavated surface; (3) displaying on the display panel information representing the desired contour of the excavated surface; and (4) controlling movement of the excavator bucket to excavate the desired contour of the excavated surface. The display panel displays a sequence of screens that convey information to the operator and permit the operator to select operational modes and to input data to define the control parameters for the various operational modes.

Abstract: A method for controlling the operation of a power excavator during a land finishing work is disclosed. In the above method, the bucket, arm and swing unit are controlled in response to output signals from a handling signal input means. Meanwhile, the boom is controlled as follows. That is, when a boom handling signal is output from the handling signal input means, the boom is controlled in response to the boom handling signal. However, when the handling signal input means does not output a boom handling signal, the boom is controlled by a geometrical operation of signals output from the boom, arm and bucket sensors and a land finishing angle for calculating reference boom angle data. The reference boom angle data is control-operated to output an automatic boom control signal, thus controlling the boom in order to move the bucket tip on a land with the land finishing angle in response to an arm handling signal output from the handling signal input means.

Abstract: A device and process for controlling the automatic operations of a power excavator are disclosed. The device has a plurality of sensors for sensing the motions of the excavator's moving parts. The device also has a controller with discriminating means. The discriminating means operates the sensed data of the sensors and discriminates the automatic operation to be performed. The controller outputs the control signals to the excavator's moving parts for automatically performed the automatic operation. The control device further includes recognizable signal output means for converting the discriminated results into recognizable signals prior to outputting the discriminated results, and confirmation signal input means for confirming the discriminated results outputted from the recognizable signal output means.

Abstract: A construction machinery having a first boom 1 rotatably mounted on a vehicle frame, a second boom 4 rotatably mounted on the first boom 1, a first boom cylinder 2 connecting the vehicle frame 3 and the second boom 4, and a second boom cylinder 5 connecting the second boom 4 and the first boom 1, characterized in that it is arranged in such a way that the drive of the working machines in the new link mechanism is controlled simply and with high precision by indicating the position or the velocity of the working machine leading end by subjecting a working machine leading end target value to coordinate conversion to the target angles for the first and second boom angles, determining the target cylinder length for the first boom cylinder 2 from the target angles for the first and second boom angles obtained by the coordinate conversion, and driving the first boom cylinder 2 according to the target cylinder length.

Abstract: A control system for automatically controlling a work implement of an excavating machine through a machine work cycle in disclosed. The work implement including a boom, stick and bucket, each being controllably actuated by at least one respective hydraulic cylinder. A plurality of command signal magnitudes associated with at least one hydraulic cylinder are stored. The command signal magnitudes are represented by a plurality of control curves, where each control curve is responsive to a material condition setting that is representative of a predetermined condition of the excavating material. A microprocessor selects one of the plurality of control curves and responsively produces a command signal having a magnitude dictated by the selected control curve. A electrohydraulic system receives the command signal and controllably actuates predetermined ones of the hydraulic cylinders to perform the work cycle.

Abstract: A system and method for providing navigation signals between first and second earthmoving or construction machines is provided. The system determines the positions of the first and second machines. The system determines a desired location of the second machine relative to the first machine based on an optimum path. This desired location is transmitted from the first machine to the second machine.

Abstract: A removal apparatus which includes a container adapted to store removed soil, which is supported from the end of a crane, which applies a downward load on the container to keep it against the contaminated soil and advancing forward. The removal apparatus features a replaceable blade which is attached at the forward end of the container at a predetermined level to define the depth of the cut. Vertical cheek plates are attached at either side of the container to cut the end of the soil at the outer edges of the blade and to provide vertical side wall support to confine the soil within the container. Front and rear dust control chambers are provided which restrict the movement of airborne contaminants. The container includes a sensor to monitor the level of contaminated soil remaining after a cut. Prior to removal, an initial survey is made of the area is made using a sensor capable of determining the level of the contaminants in the soil.

Abstract: A snow plowing system utilizing a wireless radio remote control to control a snow plow mounted to the front of a vehicle. The plowing system comprises a snow plow blade, mounting mechanism connected to the vehicle for mounting the snow plow blade to the vehicle, the snow plow blade being connected to the mounting mechanism, a transmitter for transmitting a signal through a receiver to actuate, a mechanism for controlling the snow plow blade, and the receiver being connected to the mechanism for controlling the snow plow blade.

Abstract: The velocity of a working tool of a hydraulic excavator can be automatically decelerated and stopped just before the working tool would encounter an obstacle. Hazard regions and decelerating regions which correspond upward, downward, forward, and other positions of the hydraulic excavator are designated and a working tool decelerating pattern V.sub.2 where the working tool velocity decreases from 100% to 0% in a decelerating region is stored in a control unit. When a working tool velocity V.sub.1 which corresponds to the amount of operations of working tool levers (1, 2) intersects with the working tool decelerating pattern V.sub.2 in a decelerating region, the working tool moves at the velocity V.sub.2 and stops just before a hazard region. A restoring pattern where the working tool is restored from a just-before-hazard position to a safety region is stored as a working tool accelerating pattern V.sub.4 where the working tool velocity accelerates from a predetermined velocity just before a hazard region.

Abstract: A multiprocessor system for an excavator is disclosed. The multiprocessor system has a joy stick which controls each of cylinders for a bucket, a dipper, a boom, a swing and/or traveling parts of the excavator and adjusts engine, pump and hydraulic valves by using microprocessors. As a result, performance and function of the excavator are improved.

Abstract: Apparatus for controlling the movement of hydraulically movable work equipment that is arranged at the end of a length-adjustable and pivotable arm, along a substantially rectilinear path of movement, the work equipment being moved with the assistance of hydraulic drive units that act on the arm in dependence on input control signals that determine the path of movement. Even in the case of non-ideal control loops for the control of the drive units, it is intended that the work equipment be moved along a desired path. For that purpose, starting from an actual position of the work equipment, a sequence of desired positions in the path of movement is ascertained and the work equipment is moved from an actual position to the next desired position, the movement into the next position not being initiated until the work equipment is located in a predetermined tolerance band about the preceding position.