Remote-Controlled Work Machine Power-Limiting Hydraulic Control
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Solution Overview
Problem
Remote-controlled work machines often face delays or inability to operate due to inadequate electricity distribution grids that cannot supply the required current, leading to increased costs and demands on the external electrical grid.
Innovation Solution
The work machine is equipped with a selectable power-limiting mode that reduces the volume of hydraulic flow to operational devices by adjusting the control valve curves, allowing it to function with reduced power and speed, compatible with lower current supplies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the work machine operates in normal power mode, then it achieves full operational speed and power, but it requires high grid current supply that is unavailable at many work locations
Solution Approach 1:
The work machine implements dynamic power mode selection, allowing the operator to switch between normal power mode and limited power mode based on the capabilities of the available electricity distribution grid. The control system dynamically adjusts hydraulic flow parameters according to the selected mode, enabling the machine to adapt its power consumption to match the grid's current supply capacity.
Solution Approach 2:
The invention changes the hydraulic system's operating parameters by adjusting the control valve curves. In limited power mode, the control valve curves are modified to reduce the volume flow from the hydraulic pump while maintaining sufficient pressure for operational functionality. This parameter change allows the machine to operate with reduced power consumption compatible with lower current supplies.
2Productivity
If the work machine uses high current to maintain full power, then it achieves maximum productivity, but it causes operational delays due to grid inadequacy
Solution Approach 1:
The work machine performs preliminary assessment of the electricity distribution grid's current supply capacity before operation begins. Based on this assessment, the operator selects the appropriate power mode (normal or limited) in advance, avoiding operational delays that would occur if the machine attempted to operate in normal mode and encountered grid limitations. This preliminary action ensures immediate compatibility between the machine's power requirements and the grid's supply capability.
3Use of energy by moving object
If the work machine operates in limited power mode, then it reduces power consumption to match available grid supply, but it reduces operational speed
Solution Approach 1:
The invention modifies the control valve curves to reduce the volume flow parameter in limited power mode. By adjusting this parameter, the hydraulic system delivers reduced flow while maintaining adequate pressure, enabling the machine to operate at reduced but still functional speeds with lower power consumption that matches the available grid supply capacity.
Data Source
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AI summary
The invention concerns a control device for a remote-controlled, electrically driven work machine (1) that can be driven such as a vehicle and that is supplied with power through an electrical cable (2, 2') intended to be connected to an electricity distribution grid, and which work machine comprises an arm (10) that can be manoeuvred in a vertical plane, which arm is rotatable for oscillation in a horizontal plane around a vertical axis (C) on the machine and is intended to support a tool (14) at its free end, a control unit (4) intended for the remote control of the work machine whereby an operator (3) walks beside the work machine and is in connection by cable or in a wireless manner with a control computer (25) that forms a part of a programmable hydraulic control system (22) that is a component of the work machine and that is based on a CAN bus, which hydraulic control system includes an electrically driven pump (19) and an electrically controlled control valve (21 a, 21 b) that supplies driving flow to the operational devices (30, 31, 32, 33) of the work machine, whereby the control unit includes a pair of control levers (4a, 4b) and associated buttons (4d, 4e) and knobs that through their influence allow the work machine to be reset into various functional or working modes for the control levers. According to the invention, the work machine (1) can be reset from a normal operating mode to an operating mode with limited power, whereby the volume of flow to the operational devices (30, 31, 32, 33) of the work machine is limited through parameter adjustment of the control curves (26a, 26b) that the programmable hydraulic system (22) that is based on a CAN bus uses to regulate the opening of the control valves (21 a, 21 b) for passage through them of hydraulic flow to the operational devices.