Cable-driven parallel robot (CDPR) is a special kind of parallel robot, which use several cables connect the base and end effector simultaneously and drive the motion of the end effector by control the lengths of cables or the positions of the cable connection points. CDPR integrates cable-driven kinematic chains and parallel mechanism theory, inherits the high dynamics and heavy load capacities of the parallel mechanism, and significantly improves the workspace, cost and energy effective.

The National Institute of Standards and Technology (NIST) has taken the lead in the research of CDPR since the 1990s, developed the RoboCrane/AMP motion platform, and continuously expanded the application of CDPRs in the fields of weapon hoisting, fire fighting in oil field and fighter spraying. In recent years, the European Union has successively launched CableBOT and HEPHAESTUS projects to promote the theoretical research on CDPRs and the applications in large-scale equipment maintenance as well as building construction. The Five-hundred-meter Aperture Spherical Radio Telescope (FAST), which is the largest single dish radio telescope in the world, innovatively adopts CDPR to break through the engineering limit of the hundred-meter scale of radio telescopes. CDPR technology enables the FAST to achieve a lightweight, large-scale millimeter-level signal reception, and a leap in sensitivity with low cost. In addition, CDPRs have been adopted in the fields of motion simulation, wind tunnel test, 3D printing, logistics, warehousing, bionics, and rehabilitation medicine. CDPR has outstanding advantages, plays an irreplaceable and important role in the fields of industry, national defense, science & technology, and contains huge economic and social benefits.

At present, the global manufacturing industry is developing in the direction of lightweight, flexibility and intelligence. As the main force of intelligent manufacturing, the R&D, manufacturing and application of robots has become an important indicator of a country's scientific and technological innovation capability and manufacturing level. Robotic research is becoming a new strategic commanding height in the global technological competition. The high performance such as high-speed, heavy load and high precision is the eternal theme of robot development from the past to the future. At the same time, facing the increasing demand for efficient and precise manufacturing of large and complex components, large workspace is also an important direction for robot development. The CDPRs have expanded the workspace of traditional industrial robots by more than two orders of magnitude and have ultra-high acceleration capabilities. The theoretical and applied research of CDPRs is of great value to achieve breakthroughs in robot performance, and to promote independent innovation and industrial development of robot technology.

In terms of robot structure, serial-parallel hybrid robots and rigid-flexible robots are important routes for the development of robotics. CDPRs reflects the high-performance development trend of robots and the advanced lightweight design concept, which has a first-mover advantage in the technical route of rigid-flexible fusion and series-parallel hybrid connection. In the future research and development of robotics, CDPR will surely appear more and more, and it will be continuously cross-mixed with the existing robotics technology.

The flexibility, unidirectional force, and continuum characteristics of cables pose challenges to the research and application of CDPRs and facilitate new theories and methods. Considering the weight and elasticity of the cables, static and kinematic analysis of CDPR couples. The resulting vibration problems are important challenges for dynamics and control of CDPRs. Theories on configuration design, kinematics and dynamics modeling, performance evaluation and optimization, and motion control of CDPRs have been established. Researchers from different countries summarized the kernel theories and developments of CDPRs, and discusses the future research focus and engineering problems based on the theoretical research and practical experience of themselves. They hope that this paper could provide systematic development context for researchers in related fields, guide the follow-up research, and promote the large-scale application of CDPRs.

Our paper "State -of-the-art on theories and applications of cable-driven parallel robots" has been published in Frontiers of Mechanical Engineering.

The online version can be accessed at this link: https://www.springer.com/journal/11465.