103 results about "Stewart platform" patented technology

A hex-axis horizontal movement dynamic simulator is aimed at Modular Design without hydraulic or pneumatic system but which were conventionally used in the so called Stewart Platform; this dynamic simulator comprises three sets of movement control unit with symmetrical structure located at the positions relative to each other forming three sides of an equilateral triangle, and a load-carrying platform which connected to the three movement control by means of three sets of universal-joint yoke mechanism each relative position located on the load-carrying platform are each other arranged to form as three sides of an equilateral triangle too; with this type of arrangement, this dynamic simulator have a 6-degree of freedom motion when a sets of movement control unit makes different rectilinear motion, the load-carrying platform will generate a combination of spatial translation motion and angular motion.

The invention discloses a multi-degree-of-freedom vehicle dynamics test platform which comprises a double-rod vertical loading hydraulic cylinder with an axial force sensor, a measurement and control system, a roller, a rotating disk, a position servo hydraulic cylinder, a six-degree-of-freedom Stewart platform, an outer rotor motor, a six-force-component sensor and the like. The use of the multi-degree-of-freedom vehicle dynamics test platform can simulate the changes of geometrical shape and mechanical properties of a road pavement and the incentive role of the changes to wheels, the exertion of any one-dimensional or multi-dimensional force in six-dimensional pavement incentive force on the wheels can simultaneously carry out pavement simulation, static load simulation and dynamic load simulation, and the wheels can change the direction relative to the roller, thereby realizing the simulation of large tire sideslip angle caused by turning of a vehicle, being capable of measuring steering angles of the wheels and six-dimensional force born on the wheels, carrying out better simulation and testing on the practical driving working status of the vehicle, realizing the comprehensive research of the multi-degree-of-freedom vehicle dynamics and providing the vehicle dynamics test platform with more excellent performances.

The invention discloses a robot single-leg assembly control development performance test platform and method. The platform comprises a gantry three-coordinate mechanical arm assembly, a robot leg connection bracket, a Stewart platform, a six-dimensional force sensor, a robot single-leg assembly and a five-dimensional force measurement platform, wherein a servo controller and a displacement sensor are integrated in the Stewart platform; the Stewart platform is invertedly arranged on a base of the robot leg bracket; the five-dimensional force measurement platform is arranged at the center of the ground below the robot single-leg assembly; and the robot leg connection bracket is fixed on a Z-axis-direction mobile supporting frame assembly of the gantry three-coordinate mechanical arm assembly. The test platform is suitable for single-leg movement and quick gait control during bionic gait generation of a four-foot or multi-foot hydraulic driving robot as well as development and research on multiple control strategies for robot load distribution, control force distribution, single-leg force feedback control and 'discrete gait and continuous force control' attitude stabilization control.

The invention belongs to the technical field of robots and discloses a 6-PSS parallel mechanism and a position forward and inverse solution method. A circular rail is arranged and provided with six sliding modules which move actively and precisely along the rail. The sliding modules are connected with the lower ends of connecting rods of a fixed length through spherical hinges correspondingly. Theupper ends of the connecting rods are connected with a motion platform through spherical hinges correspondingly. According to the 6-PSS parallel mechanism and the position forward and inverse solution method, six-degree-of-freedom motion of the motion platform can be achieved, the mechanism is remarkably characterized in that the motion platform can rotate at any angle around the vertical axis, the motion flexibility of the mechanism is improved, and the posture adjustment work space is expanded; and the mechanism can be applied to multiple occasions including light radar antenna pedestals, radiotelescope feed source supporting platforms, motion simulators and the like. The mechanism and method provided by the invention are easy to operate, and the problem that a Stewart platform traditional six-degree-of-freedom parallel robot is limited in work space is effectively relieved; and the motion platform moves by driving the six parallel sliding modules, and the motion speed of the motionplatform is increased.

The invention discloses a cantilever tail end vibration analysis and error compensation method, which comprises the following steps: simulating low-frequency vibration of the cantilever by a base body Stewart platform, and compensating the space error of an actuator tail end by a positioning Stewart platform based on the value measured by a laser displacement transducer; and simulating high-frequency vibration of the cantilever by a scaled-down cantilever based on the parameterized standard excitation, measuring the space error of the actuator tail end based on a cantilever distribution parameter dynamic model and a force sensor, and compensating the space error by the positioning Stewart platform based on the measuring, wherein the compensation effect is assessed by the laser displacement transducer. According to the invention, the space error of the cantilever tail end is measured based on a cantilever precise dynamic model and the force sensor, which improves the error compensation precision and efficiency of the positioning Stewart platform; and meanwhile, based on the space error caused by the positioning Stewart platform in compensating high/low-frequency vibration, the static and dynamic positioning accuracy of the actuator can be improved.

The invention discloses a six-dimensional force transducer calibration device which comprises a base, a sensor fixing platform, a calibration operation platform, an upper three-jaw chuck, a lower three-jaw chuck, electric push cylinders, standard one-way force sensors and universal hinges. The calibration operation platform, the electric push cylinders, the universal hinges and the base form a Stewart platform structure. By the adoption of the Stewart platform structure, a Stewart platform can perform any spatial movement in the Stewart structure, loading of any spatial force can be realized, sensors or loading force sources do not need to move, and calibration error generated from moving of the sensors or the loading force sources is decreased. The electric push cylinders serve as the loading force sources, and automatic, continuous and highly accurate loading can be realized. Date measured by the six standard one-way force sensors and data outputted by calibration sensors are subjected to comparative analysis, and the standard one-way force sensors are high in accuracy and can accurately calibrate performance of the six-dimensional force sensors.

A manipulator tool for installing and retrieving objects from a fixed or floating structure in a subsea tidal environment includes an articulated arm attached to the fixed or floating structure. The tool may be configured to compensate for movement of the objects due to tidal forces. In one embodiment, a stewart platform is used as a compensator to maintain the objects in a substantially stationary position in the tidal environment.

The invention discloses a quasi-zero stiffness vibration isolation and energy collection system based on a Stewart platform and relates to the technical field of vibration isolation. The system devicecomprises an upper platform, a lower platform and six supporting legs. Each supporting leg comprises an outer sleeve, a connecting rod, a guide rod, an electromagnet, a first annular permanent magnet, a coil, a second annular permanent magnet and a diaphragm spring, wherein the first annular permanent magnet, the coil, the second annular permanent magnet and the diaphragm spring are up-down successively fixed in the outer sleeve. A first guide part is arranged in the first annular permanent magnet. A second guide part is arranged in the second annular permanent magnet. The guide rod is sleeved in the first guide part and the second guide part. The lower end of the guide rod is fixedly connected with the diaphragm spring. The electromagnet is fixed to the guide rod and arranged in a spaceformed by enclosing the first annular permanent magnet, the second annular permanent magnet and the coil. The upper end of the guide rod is connected with the upper platform through a hinge piece. Thelower end of the connecting rod is connected with the lower platform through a hinge piece. According to the system, rigidity is adjustable, low-frequency vibration can be well restrained, energy collection is achieved, and energy can be input to the outside.

The invention discloses an electromagnetic quasi-zero stiffness vibration isolation system based on the Stewart platform. The electromagnetic quasi-zero stiffness vibration isolation system based on the Stewart platform comprises an upper platform and a lower platform, the upper platform and the lower platform are oppositely arranged, six vibration isolation devices are arranged between the upperplatform and the lower platform, six vibration isolation devices are arranged according to a Stewart platform mode, a first diaphragm spring is arranged at one ends of the vibration isolation devicesin a sleeved mode, the other end of the vibration isolation device is sleeved with a second diaphragm spring, each vibration isolation device comprises a guide shaft, a magnet set is arranged on the outer side of the guide shaft, a coil set is arranged on the outer side of the magnet set, a gap is formed between the magnet set and the coil set, and an outer cylinder is arranged on the outer side of the coil set. According to the electromagnetic quasi-zero stiffness vibration isolation system, the adjustable nonlinear negative stiffness is realized by utilizing the mutual acting force between the permanent magnet and the conductive coil, the first diaphragm spring and the second diaphragm spring provide positive rigidity, and the quasi-zero rigidity near the working position is achieved through combination of positive and negative rigidity; the electromagnetic quasi-zero stiffness vibration isolation system has the advantages of being simple in structure, the rigidity is controllable and the like, the inherent frequency of the vibration isolation system is effectively reduced, and further the vibration isolation frequency band is widened.

The invention discloses a six-freedom parallel control self-correction return apparatus for space vector force loading. The apparatus comprises a loading point 32, a loading part 33, a moving platform 1, a fixed platform 4 and six self-correction return parts, wherein the moving platform 1 and the fixed platform 4 are connected through the six self-correction return parts, and connection relations are arranged according to six-freedom parallel Stewart platform structure. Each self-correction return part comprises a first ball hinge 41, a universal flexible element 42, a force transducer 43, a telescoping rod 44, a driving mechanism 45 and a second ball hinge 46, wherein the universal flexible element 42 is an elastic element only transmitting axial forces and is connected with the moving platform 1 through the first ball hinge 41, the other end of the universal flexible element 42 is connected with a telescoping rod driving mechanism through the force transducer 43, the telescoping rod driving mechanism comprises the telescoping rod 44 and the driving mechanism 45, and the other end of the driving mechanism 45 is connected with the fixed platform 4 through the second ball hinge 46.

The invention relates to an active compliance control strategy of a Stewart platform and belongs to the control field of a Stewart platform. The strategy is the active compliance control strategy of aStewart platform that takes a six-dimensional force transducer as a collection element through a neural network. Through combination of a track plan and the neural network, a relation model between the movement track of the platform and an output load can be obtained under a condition that platform design parameters are unknown. After an expected load applied a test piece is input into the model,a movement track of the platform, which enables the test piece to reach the expected load, can be obtained, and then a control method enabling the Stewart platform to take the load as a parameter canbe realized by means of displacement control. Compared with the prior art, the active compliance control strategy avoids conventional complex decoupling and coupling problems in control of the Stewart platform. Moreover, the design of the control strategy needs no prior information of equipment, is high in fault tolerance rate, and is not disturbed by the assembly errors, measurement errors and other factors.

Disclosed is an automobile racing simulator capable of achieving six space freedom degrees. On the basis of a classic Stewart platform, an automobile racing seat, a displayer fixing frame assembly, pedals and a steering wheel are connected to an automobile body, a person sits on the automobile racing seat, the steering wheel and the pedals are controlled according to game scenes displayed in liquid crystal displayers, and the person can have the acceleration, deceleration, sudden turning, impacting and other true experience feelings. The automobile body, a base and a displayer support are formed by bending and welding seamless polished pipes, the appearance is attractive and fashionable, the three liquid crystal displayers are fixed easily, rapidly and conveniently, and maintenance is convenient.

The invention discloses an improved ankle rehabilitation mechanism based on a Stewart platform. The improved ankle rehabilitation mechanism based on the Stewart platform comprises six telescopic branch chains; the telescopic branch chains are composed of motors, speed reducers and lead screws, and are symmetrically distributed relative to an intermediate plane at initial positions, and the motorsdrive the speed reducers and the lead screws to convert the rotational motion of the motors into linear motion; the telescopic branch chains are connected with a static platform and a movable platformthrough hinges respectively. The improved ankle rehabilitation mechanism based on the Stewart platform has the advantages that a parallel mechanism is improved based on the Stewart platform accordingto working space required for the rehabilitation of the ankle, the accessible working space is space formed by translating and scaling a prismatic section in the direction perpendicular to the staticplatform, the skillful working space has a wide range of angular motion, and the functional requirements of the ankle rehabilitation robot can be better met.

The invention discloses a Stewart platform parallel mechanism limiting measurement and control apparatus, and a measurement and control method thereof. The apparatus comprises a base. A hook joint is arranged on the base. A first attitude sensor is fixedly arranged on the base. A second attitude sensor is fixedly arranged on the inner ring of the hook joint. A third attitude sensor is fixedly arranged on a motion platform. An absolute value type stay wire encoder is further fixedly arranged on the inner ring of the hook joint. The stay rope of the absolute value type stay wire encoder is linearly connected with one point on the center line of the motion platform and the point where the axial line of the hook joint outer ring shaft and the axial line of the hook joint inner ring shaft intersect. A data processing module is further arranged. The Stewart platform parallel mechanism limiting measurement and control apparatus, and the measurement and control method thereof are simple and reliable.

The invention discloses a Stewart stable platform control method based on an RBF neural network, and the method comprises the following contents of establishing a kinematic model of the Stewart stableplatform according to the principle of robot kinematics, and obtaining a Jacobian matrix of the Stewart stable platform about the posture through total differentiation; establishing a dynamic model of the Stewart stable platform by using the Lagrange's equation method and combined with the Jacobian matrix; mathematically modeling the single channel of Stewart according to the dynamic model to obtain a transfer function, and then adopting a PID control algorithm and a series control strategy to control the position of the single channel; constructing a posture control strategy of the Stewart stable platform, and stably controlling the Stewart platform by using the strategy. The method provided by the invention can effectively overcome the assembly error and model error of the Stewart stable platform, and improves the tracking accuracy and anti-interference ability.

The invention discloses a three-axis vibration test table and a control method. The three-axis vibration test table comprises a frame body, a bottom carrier board, a top carrier board, a test platformand a cross guide mechanism, wherein the bottom carrier board is driven to take a translational motion up and down; the top carrier board is arranged above the bottom carrier board and can be drivento take a translational motion relative to the bottom carrier board; the test platform is fixedly arranged on the top carrier board; the cross guide mechanism comprises two groups of linear guide parts correspondingly and perpendicularly arranged at an interval, a middle plate positioned between the two groups of linear guide parts and guide parts respectively arranged on two lateral surfaces of the middle plate and correspondingly matched with the linear guide parts; and the cross guide mechanism is arranged between the bottom carrier board and the top carrier board. The three-axis vibrationtest table is high in expansibility; and when the three-axis vibration test table is used as a vibration source, a workpiece can be additionally and randomly arranged on a vibration platform and for example, a high-frequency vibrator is additionally arranged, so that application of the three-axis vibration test table is further expanded.

A coil spring modeling apparatus includes a first attachment member disposed on a lower spring seat, a second attachment member disposed on an upper spring seat, an actuator unit formed of a Stewart-platform-type parallel mechanism, a hydraulic pressure supply device, a torsion detection mechanism, and a controller. The torsion detection mechanism is constituted of displacement gauges such as a linear variable differential transformer. The displacement gauges are provided on hydraulic cylinders, and detect amounts of displacement relative to the reference lengths of the hydraulic cylinders, respectively. The controller calculates a relative torsional angle between the first attachment member and the second attachment member based on the detected displacement.

The invention relates to a cooperative control method of a Stewart platform, and belongs to the technical field of parallel robot control. In an upper computer controller, a cooperative control algorithm is adopted, non-interactive control signals in each independent controller are coordinated as a whole, and the problems of position mismatching and over-fitting of electric cylinders in parallel platform pose control caused by different loads or other factors are solved. Meanwhile, an ADRC is adopted, the uncertainty of internal modeling is estimated, external disturbance is compensated, the control precision is improved to a certain degree, and the high-performance pose control requirement is met. According to the cooperative control method of the Stewart platform, the control precision can be improved, the cooperative effect of the electric cylinders in the transition process is improved, the problems of deformation and the like caused by unbalanced load distribution among the electric cylinders are reduced, the joint burden of the electric cylinders is relieved, the service life of the electric cylinders is prolonged, and economic benefits are improved.