Kelvin Chen Chih Peng

Hand-Motion Crane Control Using Radio-Frequency Real-Time Location Systems

Human operators have difficulty driving cranes quickly, accurately, and safely because the heavy structure of the crane responds slowly and its payload oscillates. Manipulation difficulty is increased by nonintuitive control interfaces (such as buttons, levers, and joysticks) that require substantial experience to master. This paper presents a new type of interface that allows operators to drive a crane by simply moving a hand-held radio-frequency tag through the desired path. Real-time location sensors are used to track the movements of the tag and its position is used in a feedback control loop to drive the crane. Unfortunately, crane movements usually induce large-amplitude payload oscillations. Therefore, an input-shaping control element is used to limit payload swing. Experimental results on an industrial bridge crane validate the controller performance.

Using Machine Vision and Hand-Motion Control to Improve Crane Operator Performance

The payload oscillation inherent to all cranes makes it challenging for human operators to manipulate payloads quickly, accurately, and safely. Manipulation difficulty is also increased by nonintuitive crane-control interfaces. This paper describes a new interface that allows operators to drive a crane by moving a hand-held device (wand or glove) freely in space. A crane-mounted camera tracks the movement of the hand-held device, the position of which is used to drive the crane. Two control architectures were investigated. The first uses a simple feedback controller, and the second uses feedback and an input shaper. Two operator studies demonstrate that hand-motion crane control is faster and safer than using a standard push-button pendent control.

Crane control using machine vision and wand following

The payload oscillation inherent to all cranes makes it challenging for human operators to manipulate payloads quickly, accurately, and safely. A new type of crane control system that allows an operator to drive a crane by moving a hand-held wand has been implemented on an industrial bridge crane at the Georgia Institute of Technology. An image processing system tracks the movement of the wand and its position is used to drive the crane. The crane was used to study the performance of human operators as they drove the crane through obstacle courses. The experimental results show that operators performed maneuvering tasks faster, safer, and more effectively when using the wand controller instead of the traditional push-button pendent controller.

Initial investigations of hand-motion crane control with double-pendulum payloads

A novel hand-motion crane control system was developed that improves performance by providing: 1) an intuitive control interface and 2) an element that reduces the complex oscillatory behaviors of the payload. Operators wearing a reflective glove drive a crane simply by moving their hand through the desired path. A crane-mounted camera tracks the glove and its position is used to drive the crane. This paper presents an initial investigation of the hand-motion crane control interface with double-pendulum payloads. Experimental results from a 10-ton industrial bridge crane demonstrate the utility of the interface and oscillation-control method.

Filtering effects on input-shaped command signals for effective crane control

Human operators have difficulty driving cranes quickly, accurately, and safely because of the slow response of heavy crane structures, non-intuitive control interfaces, and payload oscillations. This paper presents a new type of interface that allows operators to drive a crane by moving a hand-held radio-frequency tag. Real-time location sensors are used to track the movements of the tag and the tag position is used in a feedback control loop to drive the crane. An input shaper is added to eliminate dangerous payload oscillations. Unfortunately, significant sensor noise can increase the energy-usage and settling-time during operation. To reduce these negative side effects, several filters are used on experimentally-acquired tag trajectories. The filtered trajectories are then used to drive crane simulations. The filter performance is evaluated with respect to the energy usage of the crane trolley, and the settling time of the crane payload oscillations. The effects of filter window lengths on these parameters are also investigated.

Crane operation using hand-motion and radio frequency identification tags

Payload oscillation inherent to all cranes makes it challenging for human operators to manipulate payloads quickly, accurately, and safely. Manipulation difficulty is also increased by non-intuitive crane control interfaces. A new type of crane control interface that allows an operator to drive a crane by moving his or her hand freely in space has been implemented on an industrial bridge crane. Real-time-location technology based on radio frequency sensors tracks the 3-D movements of a small tag held in the operators hand. The tags position is then used to drive the crane. Simulations of the crane dynamics and hand-motion control were compared with actual experimental data. The results show that a combination of aggressive PD feedback control gains and an input shaper is able to generate the desired characteristics of fast crane response and low residual oscillations.

Crane Operation Using Hand-Motion and Machine Vision

Payload oscillation inherent to all cranes makes it challenging for human operators to manipulate payloads quickly, accurately, and safely. A new type of crane control interface that allows an operator to drive a crane by moving his or her hand freely in space has been implemented on an industrial bridge crane. An image processing system tracks the movement of a glove worn on the operator’s hand and its position is then used to drive the crane. Matlab simulations of the crane dynamics and hand-motion control were compared with actual experimental data. The results show that a combination of aggressive PD gains and an input shaper is able to generate the desired characteristics of fast payload response and low residual oscillations.Copyright

Determination of control parameters for a Radio-Frequency based crane controller

Human operators have difficulty driving cranes quickly, accurately, and safely because of the sluggish response of the massive structure and large payload swings. Manipulation difficulty is also increased by non-intuitive crane-control interfaces that consist of buttons and levers. A new type of crane-control interface allows operators to drive a crane by simply moving a small radio frequency emitter through the desired path. Real-time-location sensors track the movements of the radio tag. The tag position is used in a proportional feedback control scheme to drive the crane trolley toward the tag. Unfortunately, the crane payload usually responds with large-amplitude swings. Feedback control of the payload swing is not implemented, due to the difficulty of measuring the payload state. Instead, an input-shaping control element is used to limit swing. Simulations of the crane dynamics are used to select a good combination of feedback gains and input-shaper parameters. Experiments performed on an industrial bridge crane verify the effectiveness of the proposed control approach.

Influence of Remote-Operation Time Delay on Crane Operator Performance

Abstract Cranes are used extensively in many industries throughout the world, in a wide array of environments, including some that are hazardous to humans. The vast majority of cranes are directly controlled by human operators. In some cases, it is necessary to remove the human operator from hazardous operating conditions, creating a crane that must be remotely operated. This, however, introduces additional challenges for the operator, who must now control the oscillatory payload while suffering from decreased perception of the environment and the potential time delays caused by remote operation. This paper presents two studies of crane operator performance with varying time delays. The results show that the type of crane control and duration of the communication time delay directly influence task completion time and difficulty. Input shaping control is shown to improve completion times and lower operator effort.

Prediction and Measurement of Payload Swing From Off-Centered Crane Lifts

When crane payloads are lifted off the ground, the payload may unexpectedly swing sideways. This occurs when the hoist cables are at an angle relative to vertical and the payload is not directly beneath the hoist. Because the hoist point is far above the payload, it is difficult for crane operators to know if the hoist cable is perfectly vertical before they start to lift the payload. Some amount of horizontal motion of the payload will always occur at lift off. If an off-centered lift results in significant horizontal motion, then it creates a hazard for the human operators, the payload, and the surrounding environment. This paper develops dynamic models of off-centered lifts and presents experimental verification of the theoretical predictions. To mitigate the detrimental effects of off-centered lifts, autonomous-centering solutions are proposed.Copyright