A method for limiting the speed of a hoist mounted to a mobile well service rig involves determining a safe speed limit that ensures the hoist's capable stopping time is less than the maximum allowed time for stopping. In some examples, the maximum allowed time for stopping is based on the wellstring's modulus of elasticity and independent of the hoist's braking characteristics. The capable stopping time, however, is independent of the wellstring's modulus of elasticity and dependent on the hoist's braking characteristics.

A method for controlling a hydraulic winch includes acquiring measurements from sensors coupled to the hydraulic winch. A first control function is computed based on the measurements. The first control function sets pressure across a variable displacement motor that produces motion of the tool string following a desired motion trajectory. A second control function is computed. The second control function sets displacement of a variable displacement pump that causes the pressure across the variable displacement motor to track the first control function. A pump command is selected based on the second control function. The pump command is transmitted to the variable displacement pump. The tool string moves responsive to the pump command.

A winding machine wherein a motor control means is able to control driving of a drive motor in a balancer mode, and the balancer mode includes a first balancer mode in which driving of the drive motor is controlled based on a first torque command value with an assist torque that assists the operating force added thereto, and a second balancer mode in which driving of the drive motor is controlled based on a second torque command value that does not assist the operating force, and a lifting/lowering position range is set to a first position range where control is performed in the first balancer mode regardless of the direction of the operating force being in either the winding up or winding down direction, and a second position range where control is performed to select whether control is performed in the first balancer mode or in the second balancer mode.

A method for controlling lifting of a hanging load using a lifting winch integrating a drum on which a lifting rope is wound coupled to the load, includes measuring a mass parameter and a lifting speed representative of a mass and of a displacement speed of the load and supervising an emergency stop which, once activated, shuts off the lifting winch. The method also includes, during an ascending of the load, comparing the lifting speed with a low threshold and a high threshold which vary according to the mass parameter, and monitoring lifting in an optimized mode in which the lifting speed when ascending is authorized below the high threshold and forbidden above the high threshold, and if the emergency stop is activated during an ascending and while the lifting speed is higher than the low threshold then an alarm is activated.

A method of controlling operation of equipment that spools cable on and off a rotatable drum, in one or more embodiments, includes obtaining video data of a position of the cable on the rotatable drum. The method can also include feeding data into a trained artificial neural network and processing the data fed into the trained artificial neural network to determine at least one of a calculated position of the cable on the rotatable drum, a calculated fleet angle, or both. The method can also include actuating the rotatable drum to one of spool cable on and off the rotatable drum.

The invention relates to a continuous cable winch comprising a drive unit (20) and an output unit (60) for applying a drive force to a cable, which output unit is coupled to the drive unit (20). According to the invention, it is proposed that the drive unit (20) has a frequency converter (30) with a primary side (32) for drawing current from a power supply system (33) and a secondary side (36) for outputting an AC voltage (U.sub.U, U.sub.V, U.sub.W), an AC motor (40) for driving the continuous cable winch (10) at a variable rotation speed (ω.sub.1), which AC motor is supplied with the AC voltage (U.sub.U, U.sub.V, U.sub.W) by the frequency converter (30), a control unit (50) which is interconnected with the frequency converter (30) and the AC motor (40) for the purpose of controlling the drive unit (20), wherein the control unit (50) is designed to change the rotation speed (ω.sub.1) of the AC motor (40) by means of the frequency converter (30).

A motor drive apparatus that can continue operation within the upper limit of system control even if a voltage drop of an AC power source occurs during operation of a motor used for a hoist or a crane is provided. The inverter control unit of the motor drive apparatus includes a speed reference setting means for setting the rotation speed of the motor, means for detecting a speed deviation between the output of the rotation speed detection means for detecting the rotation speed of the motor and the output of the speed reference setting means, means for controlling the output current of the inverter according to the output of the speed deviation. The speed reference setting means includes a correction circuit for correcting an external speed command given from outside. The correction circuit corrects the external speed command according to a deviation between a detection value of a DC voltage and a first reference value when a voltage drop signal is received from the voltage drop detection means, and makes the corrected speed command as the output of the speed reference setting means.

A control system for a rescue hoist attached to an aircraft is disclosed. In various embodiments, the control system includes a first bus extending between a control module of the rescue hoist and a control input device; and a second bus extending between the control module of the rescue hoist and the control input device. The first bus is configured to transmit a first signal from the control input device to the control module and the second bus is configured to transmit a second signal from the control input device to the control module, both the first signal and the second signal being generated by the control input device in response to a manipulation of the control input device.

A system for controlling a winch assembly includes a rotatable winch drum with an attached cable. A winch motor is configured to rotate the winch drum. A sensor is configured to generate signals indicative of the number of layers of the winch cable on the winch drum. A winch controller is configured to receive a control input requesting a selected rotation of the winch drum, receive the signals from the sensor, determine a number of layers of the winch cable disposed on the winch drum, and generate control commands to control the winch motor to rotate the winch drum based on the control input and the number of layers of the winch cable. The control command rotates the winch drum to produce a substantially constant line speed based on the selected control input independent of the number of layers determined to be disposed on the winch drum.

Methods and apparatus for monitoring windlass rotation are provided to determine the real time rate and length of rode release when anchoring a boat. The rotation can be monitored in real time using directional sound and/or electromagnetic radiation receivers and/or transmitter in a module attached to the windlass. Another windlass module can monitor windlass rotation using micro-electromechanical systems (MEMS) components such as accelerometers, magnetometers, gyroscopes, and/or inertial measurement units (IMU) to sense motion and/or position.