Digging Head Velocity Control via Dual Winch Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current digging and drilling machines face challenges in maintaining precise control over the velocity of descent and ascent of digging heads, especially at low velocities, leading to inefficiencies and increased costs due to the limitations of existing winch systems, which struggle to handle low speeds and result in prolonged operation times and increased production costs.
Innovation Solution
A control system utilizing two winches with motors and a sophisticated control unit that adjusts the running velocities of the load-bearing cable to achieve precise control over the digging head's movement, allowing for fine adjustments of descent and ascent velocities, even at very low values, by differentially winding and unwinding the cable between the two drums.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single winch with a high-speed hydraulic motor is used, then the digging head can be moved at high velocities, but the winch cannot operate at very low velocities (below 50 revs per minute) without drastic drop in efficiency and torque
Solution Approach 1:
The system dynamically switches between two winches based on the required velocity. Winch 1 (with high-speed motor) operates at high velocities while Winch 2 (with low-speed motor) takes over at very low velocities. This dynamic allocation ensures each motor operates within its efficient range, resolving the contradiction between high-speed capability and low-speed efficiency.
Solution Approach 2:
The single winch function is segmented into two specialized winches: Winch 1 optimized for high velocities and Winch 2 optimized for very low velocities. Each winch has its own motor sized and designed for its specific operating range, eliminating the need for a single motor to compromise between conflicting velocity requirements.
2Speed
If the load-bearing cable is relayed through many pulleys to multiply pulling force, then very low velocities can be achieved, but the amount of cable to be stored on the drums increases substantially, forcing the use of very bulky winches
Solution Approach 1:
The cable storage function is segmented between two winches. Each winch drum stores only the cable required for its specific operating range, rather than both winches needing to store the entire cable length. This segmentation reduces the volume requirement for each individual drum while maintaining the capability to achieve very low velocities when needed.
Solution Approach 2:
The system changes the operational parameters by switching between two different winch configurations. Winch 2 is specifically designed with a motor optimized for very low velocities (down to 0.1 m/min) without requiring excessive cable multiplication through pulleys, thus achieving low velocity without proportionally increasing drum volume.
3Speed
If the number of pulleys is increased to control very low velocities, then the pulling force is multiplied, but the descent and ascent times of the digging heads at the start and end of digging are lengthened
Solution Approach 1:
The system dynamically selects the appropriate winch based on the operational phase. During digging operations requiring very low velocities, Winch 2 is engaged. During rapid ascent and descent operations, Winch 1 provides faster response. This dynamic selection optimizes both velocity control and operational time, preventing the time loss that would result from using high pulley multiplication during rapid movements.
Solution Approach 2:
The control unit acts as an intermediary that intelligently selects which winch to operate based on the required velocity and operational context. This mediation ensures that the system uses the optimal winch for each situation, balancing the need for low velocity control with the need for rapid positioning during non-digging phases.
4Productivity
If very heavy digging heads are used to increase digging efficiency in difficult earth, then the thrust on cutting elements is increased, but the winch must develop very high pulling force, complicating the movement system
Solution Approach 1:
The pulling force requirement is segmented between two winches with different motor capabilities. Winch 2 is specifically designed with a motor optimized for high torque at very low velocities, capable of handling the high pulling forces required for heavy digging heads in difficult earth. This segmentation allows the use of heavy, efficient digging heads without overcomplicating the overall winch system, as each winch is specialized for its force and velocity requirements.
Data Source
Figure 1
Figure 2
AI summary
Control system (40) for a machine for digging and/or drilling earth, wherein the machine for digging and/or drilling earth (10) comprises a digging head (11) arranged to dig the soil, a flexible load-bearing element (12) arranged to support the digging head (11) during normal operation, at least a first (13) and a second winch (14), each of which in turn comprises a drum (32, 33) about which at least part of the flexible load-bearing element (12) can be wound, and a motor (30, 31) arranged to actuate the drum (32, 33); the control system (40) has an electronic control unit (43) adapted for controlling the movement of the winches (13,14), and velocity sensor means arranged in each branch of load-bearing cable (12) coming out from the winches (13,14) adapted for monitoring the movement of such a load-bearing cable.