39 results about "Holonomic constraints" patented technology

The invention discloses an unmanned path planning method, a system and a device thereof. The method comprises the following steps: acquiring environment perception information and vehicle positioningand navigation information, wherein the environment perception information contains barrier information, curb information and lane line information, and the vehicle positioning and navigation information contains vehicle pose and a target path; conducting subpath generation according to the environment perception information and the vehicle positioning and navigation information to obtain a candidate subpath which satisfies vehicle constraints; conducting collision detection on the candidate subpath which satisfies vehicle constraints, so as to obtain a collisionless candidate subpath; conducting subpath search on the collisionless candidate subpath by A* search algorithm; and obtaining a vehicle local path according to the subpath search result. The requirement on storage space is low, and the requirement on nonholonomic constraints of vehicles can be met. The method of the invention has advantages of good adaptability and good extensibility, and can be widely applied in the field ofautomatic drive.

The invention discloses an enhanced map learning path planning method for an indoor mobile robot. The method includes the steps that (1) ambient environment information is acquired, and an obstacle probability density model is established; (2) path planning is carried out through a greedy algorithm and an enhanced map learning method; (3) path selection and self-adaptation speed strategy adjustment are conducted on the indoor mobile robot. By the adoption of the enhanced map learning path planning method, a current optimal path can be planned in real time according to the current condition of the indoor mobile robot and the inherent non-holonomic constraint of the robot, meanwhile, the obstacle crossing ability, the target point convergence ability and the planning efficiency of the indoor mobile robot can be considered through the self-adaptation speed strategy adjustment, and therefore the indoor mobile robot can arrive at a specific location safely and effectively.

The invention discloses a collaborative path planning method for a kinematic redundant two-arm space robot. The collaborative path planning method for the kinematic redundant two-arm space robot comprises the following steps that a dynamic equation and a kinematic equation of a space robot system are established; a redundant solution of an inverse kinematics equation of an end-effector is solved,and a system non-holonomic constraint equation is obtained through a momentum conservation equation; a task space constraint equation of the relationship between the end-effector motion and the attitude of a base is obtained through the system non-holonomic constraint equation; the path planning of the end-effector in a task space is obtained by using a quintic bezier curve, and path execution time is determined by the velocity and acceleration boundary of the end-effector; and the joint motion trajectory planning corresponding to different task priorities is obtained through the end-effectormotion equation and the task space constraint equation. The collaborative path planning method of the space two-arm robot is implemented, various tasks can be performed according to the priorities ofthe tasks such as a multi-arm collaborative task and a dynamic balancing task, and the operation ability of a space manipulator is greatly expanded.

The invention relates to an improved method for planning paths of driverless vehicles by the aid of rapidly random-exploring trees. The improved method is characterized by particularly comprising steps of 1), searching and acquiring an initial path from a starting point to an end point by the aid of RRT (rapidly random-exploring tree) algorithms; 2), pruning the initial path by the aid of one-waypruning processes to obtain preliminary pruned paths; 3), further reducing the lengths of the preliminary pruned paths by the aid of bidirectional pruning processes; 4), removing sharp included angleson the paths by the aid of peak clipping processes; 5), carrying out smoothing processing on the paths without clipped peaks to obtain follow paths of the driverless vehicles. Compared with the priorart, the improved method has the advantages that the paths are short, non-holonomic constraints are taken into consideration, and the like.

The invention discloses an automatic parking locus optimization method based on a full-simultaneous dynamic optimization framework, and brings forward a vehicle-environment integrated modeling dynamic optimization framework based on full-simultaneous solution strategy, for the purposes of solving the problem of safe parking at a narrow parking space within shortest time due to fast rhythm of cities, effectively eliminating influences exerted by different parking space shapes on locus planning strategies and optimizing a safe bump-free locus which has nonholonomic constraints and satisfies low-speed parking of vehicles within the shortest time. The method provided by the invention is crucially characterized in that vehicle-parking space obstacle avoidance integrated modeling is realized by use of an MPCC mathematic optimization technology, and at the same time, can optimize correlation indexes of vehicle kinetics and dynamics. According to the method, control information such as the speed, the front-wheel corner, the accelerated speed, the front-wheel angular velocity and the like of a vehicle tracking optimization locus can be directly obtained, and actual parking assistance is facilitated.

The invention discloses an error model predictive control method based on kinematics modeling of omnidirectional mobile robots. The error model predictive control method comprises the following stepsthat S11, a velocity constraint kinematics model is established between FM-OMR four Mecanum wheels; S12, a tracking error kinematics model of a FM-OMR is established; S13, aiming at the trajectory tracking problem of the FM-OMR and the tracking error kinematics model, an error model predictive controller combined with a velocity constraint equation is designed; and S14, according to the error model predictive controller, effective trajectory tracking parameters between the omnidirectional mobile robots are controlled so as to enable tracking errors between the omnidirectional mobile robots toremain unchanged. According to the error model predictive control method based on the kinematics modeling of the omnidirectional mobile robots, the error model predictive control method based on the trajectory tracking error kinematics modeling is provided aiming at the omnidirectional mobile robots with the four Mecanum wheels, the non-holonomic constraint problem of the effective trajectory tracking control is solved, and the accuracy and the validity are realized.

The invention discloses a unified dynamic modeling method of a generalized system of a crawler-type mobile manipulator. The core thereof comprises the following steps of: utilizing absolute coordinates to calculate kinetic energy and potential energy of the crawler-type mobile manipulator; using lagrangian dynamic method of a robot to carry out unified dynamic modeling to the crawler-type mobile manipulator; and rewriting the modeling into the unified dynamic modeling under the generalized system as the mobile manipulator is a complex system and a mobile platform has incomplete constraint. The invention avoids the error caused by that the coupling and mutual influence of the mobile platform and the manipulator which are respectively modeled and controlled when the mobile manipulator is researched originally, simultaneously has strong theoretical property, clear thinking and easy realization of programming and achieves the purpose of controlling the type of mobile manipulator precisely.

The invention discloses an orbit expansion based multi-robot tracing formulation control method, comprising the following steps of: a) for a group of target orbit in a plane, expanding vectors of the target orbit, which point to each point on the orbit along the center of the target orbit, into an orbital cluster equivalent to an orbital function, and determining the movable range of robots; b) calculating tracing error by virtue of the orbital function, and designing the virtual angular velocity of the robots to ensure the tracing error to meet design requirements; c) calculating the generalized arc length and differential coefficient of the generalized arc length when the robots move along the orbit, by virtue of the orbital function and the target orbit, and designing the control force of the robots by virtue of neighbor information obtained by communication to realize formulation; d) calculating the error between the real angular velocity and the virtual angular velocity, and designing the control moment of force of the robot to complete tracing; and e) completing motion control on the robots by virtue of a servo system. The orbit expansion based multi-robot tracing formulation control method disclosed by the invention is especially applicable to nonholonomic constraint dynamic robots and simple and convexly- closed orbits. The method is simple and reliable, has higher accuracy and can be applied to multi-robot optimized information acquisition and the like.

The invention discloses a homography matrix based visual servo control method for a shortest path. The method comprises steps as follows: motion of a robot is decomposed into three stages, firstly, the robot is rotated to face a position point where a target image is located, the position point where the target image is located is called a target point for short, then the robot is horizontally moved to the target point, finally, the robot is rotated to an angle of a target pose, and the robot motion can be controlled according to corresponding control laws at each stage. According to the method, elements in a homography matrix are directly utilized to constitute error functions, homography matrix decomposition is not required, robustness for camera parameters and image noise is better, and meanwhile, the problems about unknown depth information of a monocular camera and nonholonomic constraint of a tracked robot are solved, so that the robot reaches the target pose stably through the shortest path.

The invention relates to a novel under-actuated robot wrist device based on nonholonomic constraint. The novel under-actuated robot wrist device based on nonholonomic constraint comprises a fixed platform, a movable platform, two branch mechanism chains, two drive power sources and a middle constraint device. The fixed platform is connected with the movable platform through the two branch mechanism chains. The two branch mechanism chains are driven by the two drive power sources for transmission through two branch mechanisms, the nonholonomic constraint is formed by the middle constraint device, and then three-freedom-degree motion of the movable platform is achieved. A three-freedom-degree parallel mechanism driven by the two power sources is adopted for three-freedom-degree motion, power sources are fewer, a wrist is small in size, low in weight and low in cost, and only a low control system is needed. The device is simple in structure and reliable in work, can serve as a joint of a robot, and is used for driving more arm joint freedom degrees through a few power sources.

The invention discloses a non-integrate teleoperation constraint control method based on complex operation tasks. The complex operation tasks are decomposed by calculating the constraint matrix CVF, and a constraint controller is designed finally. Compared with a general mechanical arm control method, the non-integrate teleoperation constraint control method has two beneficial effects on the aspects of the task level and control method for complex space control tasks, specifically, the control tasks which a mechanical arm needs to complete in the space include approaching the target, tracing the path, avoiding obstacles and the like, and since proper movement spinor collections are selected according to the different operation tasks so as to establish the constraint matrix, the method has a better capacity of adapting to the complex tasks compared with prior methods; and besides, by means of the non-integrate teleoperation constraint control method, operation is more flexible, an operator can control the mechanical arm to move only in the horizontal motion direction or rotation direction, no extra constraint is needed, and accordingly the stress of the operator is relieved.

The invention provides a state estimation method and system under heading constraint. The method comprises the following steps: under the condition that heading is known, augmenting a state vector anda covariance matrix by utilizing nodal increment of a constraint straight line, and augmenting an original state equation; calculating an initial value; constructing pseudo measurement based on a position constraint relation and a corresponding speed constraint relation; augmenting a measurement equation by utilizing the pseudo measurement; based on the augmented state equation and the augmentedmeasurement equation, and initial values of the state vector and the covariance matrix, carrying out extended Kalman filtering to obtain a filtering result of a target position. By adopting the stateestimation method and system under the heading constraint, the state estimation problem under incomplete constraint conditions is solved; prior known information is sufficiently utilized and wastes ofthe information are avoided.

An embodiment of the invention discloses a method for optimizing joint angles of under-actuated mechanical arms on the basis of improved particle swarm algorithms. The method includes building planarthree-degrees-of-freedom passive-active-active type (PAA type) under-actuated mechanical arm kinetic models; reducing order of each under-actuated mechanical arm kinetic model with non-holonomic constraint characteristics by the aid of back-stepping control thoughts to obtain two passive-active type (PA type) subsystems, and making relations between the joint angles and the locations of the tail ends of mechanical arms definite; utilizing difference values of the locations of the tail ends of the under-actuated mechanical arms and target locations as target functions, leading in simulated annealing Metropolis acceptance criteria and congestion degree factors of artificial fish school algorithms and solving the corresponding optimal joint angles for reaching the target locations. Accordingto the technical scheme, the method has the advantages that the local optimization trapping probability of optimization algorithms can be lowered during under-actuated mechanical arm location control,and the solving precision can be improved.

The invention discloses a mechanical modeling method for a nonholonomic constraint system. The mechanical modeling method comprises the steps of introducing an intermediate variable to describe a nonholonomic constraint relation according to the complexity of nonholonomic constraints when constraint analysis is carried out; revealing independent generalized velocity information included in kinetic energy through the constraint analysis, extracting a coefficient of a product item of independent generalized velocity and defining the coefficient as the intermediate variable, and changing the kinetic energy into a new form of expression; in a modeling process, calculating partial derivatives of some function variables to generalized coordinates or total derivatives of the function variables to time massively, establishing a function-variable implication relation table and introducing composite derivation to solve by analyzing a variable subordinate structure; and defining several structural arrays to store calculation results since the calculation of the influence of the nonholonomic constraints on the system is more complex. In order to avoid a model expansion problem caused by back substitution of the intermediate variable, the calculation expression of the model needs to be outputted in a reverse order.

An online optimization calmness control method for a wheel type movable stage robot aims at a requirement for realizing calmness controlling of the wheel type movable stage robot in a non-complete restraining condition. Firstly, through defining a discrete time three-order dynamics model of the wheel type movable stage robot and a randomly selected initial time limited time window control sequence, a calmness control error sequence in a time window and gradient of the error sequence relative to a controlled input sequence are calculated. Then a Newton's method is utilized for establishing an updating mechanism for each sampling time control sequence. Furthermore according to a rolling optimization control principle, a controlled input amount at each sampling time point is calculated, thereby realizing calmness controlling to the wheel type movable stage robot. The online optimization calmness control method according to the invention has advantages of easy understanding, small number of setting parameters, high versatility and simple online calculation. Furthermore the online optimization calmness control method satisfies a requirement for high real-time performance in quick calmness controlling of the wheel type movable stage robot.