Search results

In large equipment and highly complex confined workspaces, the maintenance is usually carried out by snake-arm robots with equal cross-sections. However, the equal cross-sectional design results in the snake arm suffering from stress concentration and restricted working space. The purpose of this paper is to design a variable cross-section elephant trunk robot (ETR) that can address these shortcomings through bionic principles.

This paper proposes a cable-driven ETR to explore the advantages and inspiration of variable cross-section features for hyper-redundant robot design. For the kinematic characteristics, the influence of the variable cross-section design on the maximum joint angle of the ETR is analysed using the control variables method and the structural parameters are selected. Based on the biological inspiration of the whole elephant trunk following the movement of the trunk tip, a trajectory-tracking algorithm is designed to solve the inverse kinematics of the ETR.

Simulation and test results show the unique advantages of the proposed variable cross-section ETR in kinematics and forces, which can reduce stress concentrations and increase the flexibility of movement.

This paper presents a design method for a variable cross-section ETR for confined working spaces, analyses the kinematic characteristics and develops a targeted trajectory control algorithm.

This paper aims to study the influence of significant design parameters of elephant trunk soft pneumatic actuator and presents maximum optimized geometric structure of the actuator using finite element method.

Analysis of variance (ANOVA) is used to examine the influence of significant parameters such as wall thickness, bottom layer thickness and gap between adjacent chambers on the performance of the soft actuator. The most influencing parameter is found to be the wall thickness compared to the gap between adjacent chambers and bottom layer thickness.

The optimization of bending moment recommends a wall thickness of 1.5 mm, a gap between the adjacent channels of 1.5 mm and bottom layer thickness of 4 mm for the actuator. The theoretical expression of mechanical parameters is described.

The design optimization of elephant trunk shaped soft actuator with respect to bending angle and force analysis has not been investigated.

The purpose of this paper is to present a new method to establish a kinematic model for a continuum manipulator, whose end can be controlled to move in a three-dimensional workspace. A continuum manipulator has significant advantages over traditional, rigid manipulators in many applications because of its ability to conform to the environment. Moreover, because of its excellent flexibility, light weight, low energy consumption, low production cost, it has a number of potential applications in areas of earthquake relief, agricultural harvesting, medical facilities and space exploration.

This paper uses basic theory of material mechanics to deduct motion equations of the manipulator. Unlike other published papers, the manipulator is not based on segments tactics, but regarded as an integrated flexible system, which simplifies its kinematics modelling and motion controlling. The workspace of the manipulator is analysed by theoretical deducing and simulation modelling. For verification of the presented theory, simulation based on ADAMS software was implemented, while a prototype of the manipulator was developed. Both the software simulation and prototype experiment show that the theoretical analysis in this paper is reasonable. The manipulator can move accurately along the desired trajectories.

This paper developed a novel and fully continuous manipulator driven by steel wires. A kinematic model of the manipulator was established. The physical manipulator developed for verifying the kinematic model can effectively track the prescribed trajectory. The presented kinematic model agrees with not only the simulation but also with the experiment.

The manipulator presented in this paper is constructed by steel wires. It possesses the advantages of structural continuity, high flexibility and low production cost. It can be extensively used in many fields, such as search and rescue robotic systems. The limitation of this research is that the dynamic model of the manipulator is not yet clear, which is one of the directions for future research.

The manipulator breaks through the limitation of the joint-type or flexible-link-type manipulator, which can also be extensively used in many fields such as search and rescue robotic systems.

The manipulator developed in this paper, currently, is a prototype under the project of “Automatic Picking Manipulator Research”. It possesses a good market value.

The value of this research is that the manipulator breaks through the limitation of the joint-type or flexible-link-type manipulator and establishes the kinematic model for a fully continuous manipulator by a simple strategy. This is the first study that uses such a strategy for establishing the motion equations of a monolithic continuum manipulator.

This paper aims to present an iterative path-following method with joint limits to solve the problem of large computation cost, movement exceeding joint limits and poor path-following accuracy for the path planning of hyper-redundant snake-like manipulator.

When a desired path is given, new configuration of the snake-like manipulator is obtained through a geometrical approach, then the joints are repositioned through iterations until all the rotation angles satisfy the imposed joint limits. Finally, a new arrangement is obtained through the analytic solution of the inverse kinematics of hyper-redundant manipulator. Finally, simulations and experiments are carried out to analyze the performance of the proposed path-following method.

Simulation results show that the average computation time is 0.1 ms per step for a hyper-redundant manipulator with 12 degrees of freedom, and the deviation in tip position can be kept below 0.02 mm. Experiments show that all the rotation angles are within joint limits.

Currently , the manipulator is working in open-loop, the elasticity of the driving cable will cause positioning error. In future, close-loop control based on real-time attitude detection will be used in in combination with the path-following method to achieve high-precision trajectory tracking.

Through a series of iterative processes, the proposed method can make the manipulator approach the desired path as much as possible within the joint constraints with high precision and less computation time.

This purpose of this study is to present a novel four-element array antenna in combination with a modified Wilkinson power divider feeding network.

The two covering bands of this planar array antenna are achieved by an Elephant trunk shape (ETS) radiating element; therefore, two frequency bands for Bluetooth (2.4 GHz) and the wireless local area network (WLAN) band (5.15-5.825 GHz) are obtained.

An improved design of the power divider with curved corners rather than the sharp edges and certain new modifications in the length of matching stubs are implemented.

This paper describes an improved four-way Wilkinson power divider with excellent loss of insertion and adequate return loss for all ports and good isolation performance within two frequency bands (2.4 and 5.5 GHz) and when loaded with array components; the modified power divider complies with the design requirements. To comprehend its behavior, numerical and experimental results are provided. The simulated and measured results indicate a proper bandwidth coverage of the suggested antenna, stable radiation patterns and high gain.

Existing devices such as robots and machine tools rely on motion generators that have been developed almost entirely from existing technology, e.g. electric motors, hydraulic/pneumatic cylinders. Consequently, modern machines are attempting to perform increasingly complicated tasks by relying on ever more complex computer programs to compensate for the deficiencies of the device actually performing the task. In chemical plants, for example, sophisicated control software is still directing valves designed and built at the inception of the plant process. Similarly, today's factory automation systems are aiming to achieve more and more difficult tasks on the assumption that a suitable “intelligent” computer program will enable existing devices to perform these tasks efficiently.

An Elephant trunk shape (ETS) radiating element is used to achieve the two covering bands of multi-input multi-output (MIMO) antenna. These frequency bands can be controlled by the length of a slot embedded in ETS. The slot length in ETS plays a defining role in controlling the impedance bandwidth (IBW) of the MIMO antenna, and its diligent adjustment of it leads to cover the frequency range of Bluetooth and Wireless Local Area Network systems.

A new MIMO antenna is introduced in this paper in conjunction with an enhanced Wilkinson power divider feeding platform.

These frequency bands can be controlled by the length of a slot embedded in ETS. The slot length in ETS plays a defining role in controlling the IBW of the MIMO antenna, and its diligent adjustment leads to covering the frequency range of Bluetooth and WLAN systems.

The proposed MIMO antenna benefits from good isolation between ports for both frequency bands. The proposed MIMO antenna is constructed on FR4 substrate with a volume of 90 × 134 × 1.6 mm3.

The purpose of this paper is to develop a tendon actuated variable stiffness double spring based continuously tapered multi-section flexible robot and study its capability to achieve the desired bending and compression for inspection in cluttered environments.

Spring-based continuum manipulators get compressed while actuated for bending. This property can be used for the advantage in cluttered environments if one is able to control both bending and compression. Here, this paper uses a mechanics based model to achieve the desired bending and compression. Moreover, this study tries to incorporate the tapered design to help in independent actuation of the distal sections with minimal effects on proximal sections. This study is also trying to incorporate the double spring based design to minimize the number of spacers in the robot body.

The model was able to produce desired curvature at the tip section with less than 4.62% error. The positioning error of the manipulator is nearly 3.5% which is at par with the state-of-the-art manipulators for search and rescue operations. It was also found that the use of double spring can effectively reduce the number of spacers required. It can be helpful in smooth robot to outer world interaction without any kink. From the experiments, it has been found that the error of the kinematic model decreases as one moves from high radius of curvature to low radius of curvature. Error is maximum when the radius of curvature is infinity.

The proposed manipulator can be used for search operations in cluttered environments such as collapsed buildings and maintenance of heavy machineries in industries.

The novelty of this paper lies in the design and the proposed kinematics for a spring-based continuously tapered multi-section manipulator.

Describes an automated robotic milking system that allows self‐milking by cows. Benefits include increased yield, improved cow welfare and reduced labour. Describes elephant‐trunk robotic arms and vision guidance system for teat acquisition.

This paper aims to present a kinematics analysis method and statics based control of the continuum robot with mortise and tenon joints to achieve better control performance of the robot.

The kinematics model is derived by the geometric analysis method under the piecewise constant curvature assumption, and the workspace and dexterity of the proposed robot are analyzed to optimize its structure parameters. Moreover, the statics model is established by the principle of virtual work, which is used to analyze the mapping relationship between the bending deformation and the applied forces/torques. To improve the control accuracy of the robot, a model-based controller is put forward.

Results of the experiments verify the feasibility of the proposed continuum structure and the correctness of the established model and the control method. The force deviation between the theoretical value and the actual value is relatively small, and the mean value of the deviation between the driving forces is only 0.46 N, which verify the established statics model and the controller.

The proposed model and motion controller can realize its accurate bending control with a few deviations, which can be used as the reference for the motion planning and dynamic model of the continuum robot.