摘要:
A control system for operating a hydraulic system (10) includes a user input device (47) which generates an input signal indicating desired movement of a hydraulic actuator (16). A mapping routine (50) converts the input signal into a velocity command indicating a desired actuator velocity. A valve opening routine (56) transforms the velocity command into a flow coefficient which characterizes fluid flow through the valve assembly (25) and from the flow coefficient produces a set of control signals designating levels of electric current to apply to valves (21-24) within the valve assembly. A pressure controller (64) regulates pressure in the supply line (14) in response to the velocity command. When the hydraulic system (10) has a plurality of functions (11,20), the control system adjusts each velocity command to equitably apportion fluid to each function, when the aggregate flow being demanded by the functions exceeds the total flow available from a source.
摘要:
A plurality of hydraulic actuators are connected between a supply line (14) and a tank return line (18). A separate desired velocity is requested for each hydraulic actuator. In response to a respective metering mode and the desired velocity for each hydraulic actuator, the flow requirements that each hydraulic actuator has from the supply and return lines are derived. A determination is made as to what fractions of the required flows can be provided by the flow levels that are available from the supply and return lines. Those fractions are used to convert the desired velocity for the given hydraulic actuator into a velocity command which indicates the velocity of the given hydraulic actuator that can be achieved with the available fluid flows. The respective velocity command is used to control the flow of fluid to each hydraulic actuator.
摘要:
A control system for operating a hydraulic system (10) includes a user input device (47) which generates an input signal indicating desired movement of a hydraulic actuator (16). A mapping routine (50) converts the input signal into a velocity command indicating a desired actuator velocity. A valve opening routine (56) transforms the velocity command into a flow coefficient which characterizes fluid flow through the valve assembly (25) and from the flow coefficient produces a set of control signals designating levels of electric current to apply to valves (21-24) within the valve assembly. A pressure controller (64) regulates pressure in the supply line (14) in response to the velocity command. When the hydraulic system (10) has a plurality of functions (11,20), the control system adjusts each velocity command to equitably apportion fluid to each function, when the aggregate flow being demanded by the functions exceeds the total flow available from a source.
摘要:
A hydraulic circuit branch includes a hydraulic actuator (16), such as a cylinder, and an assembly (25) of one or more electrohydraulic proportional valves (21-24) connected in series between a pressurized fluid supply line (14) and a tank return line (18). The force acting on the hydraulic actuator (16) is determined by sensing fluid pressures produced by the hydraulic actuator. Pressures in the supply and tank return lines also are sensed. The sensed pressures and a desired velocity for the hydraulic actuator (16) are employed to determine an equivalent flow coefficient, which characterizes fluid flow through the hydraulic circuit branch, either a conduction or restriction coefficient may be derived. The equivalent flow coefficient is used to determine how to activate each electrohydraulic proportional valve to achieve the desired velocity of the hydraulic actuator. The equivalent flow coefficient also is employed to control the pressure levels in the supply and tank return lines (14, 18).
摘要:
A control system for operating a hydraulic system (10) includes a user input device (47) which generates an input signal indicating desired motion, such as a desired velocity, of a hydraulic actuator (16). A mapping routine (50) converts the input signal into a command. A valve opening routine (56) transforms the command into a flow coefficient which characterizes fluid flow through the valve assembly (25) and from the flow coefficient produces a set of control signals designating levels of electric current to apply to valves (21-24) within the valve assembly. A pressure controller (64) regulates pressure in the supply line (14) in response to the command. When the hydraulic system (10) has a plurality of functions (11,20), the control system adjusts each command to equitably apportion fluid to each function, when the aggregate flow being demanded by the functions exceeds the total flow available from a source.
摘要:
A programmable controller, for operating a machine such as one having a hydraulic system, includes a memory that stores a plurality of software function routines. A memory contains a first data file with address pointers to the function routines where the address pointers are listed in the order that the function routines may be executed. A second data file has a separate record associated with each of the address pointers and each record identifies the data variables required by the corresponding function routine. A third data file contains information about each of the variables. A code sequencer accesses the first data file and directs execution of the function routine in the order designated by the pointers. As each function routine executes, the respective record in the second data file is used to access the required variable information.
摘要:
An apparatus and method for creating vibration of an appendage (126) of a work vehicle (100) is disclosed. The apparatus includes a hydraulic cylinder (210), first and second valve assemblies (235,240,245,250), and a control element (280). The hydraulic cylinder (210) is coupled between a first portion (120) of the work vehicle (100) and the appendage (126) and includes a first chamber (225), a second chamber (230), and a piston (215). The first and second valve assemblies (235,240,245,250) respectively govern whether hydraulic fluid is provided from a pump (255) to, or to a tank (260) from, the first (225) and second (230) chambers. The control element (280) automatically causes a status of the second valve (235,240) assembly to repeatedly alternate with time so that the vibration occurs at the piston (215) and is in turn provided to the appendage (126).