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This paper aims to present a new trajectory optimization approach targeting spray painting applications that satisfies the paint thickness requirements of complex-free surfaces.

In this paper, a new trajectory generation approach is developed to optimize the transitional segments at the junction of adjacent patches for straight line, convex arc and concave arc combinations based on different angles between normal vectors of patches. In addition, the paint parameters including the paint gun velocity, spray height and the distance between adjacent trajectories have been determined in the generation approach. Then a thickness distribution model is established to simulate the effectiveness of trajectory planning.

The developed approach was applied to a complex-free surface of various curvatures, and the analysis results of the trajectory optimization show that adopting different transitional segment according to the angle between normal vectors can obtain the optimal trajectory. Based on the simulation and experimental validation results, the proposed approach is effective at improving paint thickness uniformity, and the obtained results are consistent with the simulation results, meaning that the simulation model can be used to predict the actual paint performance.

This paper discusses a new trajectory generation approach to decrease the thickness error values to satisfy spray paint requirements. According to the successfully performed simulation and experimental results, the approach is useful and practical in overcoming the challenge of improving the paint thickness quality on complex-free surface.

The purpose of this paper is to give a novel sensor‐less manipulation strategy for the high‐precision assembly of an eccentric peg into a hole.

Based on the authors' previous work on the attractive region, this paper proposes the sensorless eccentric peg‐hole insertion strategy. The analysis is based on the visible strategic behaviors by decomposing the high‐dimensional configuration space of the eccentric peg‐hole into two low dimensional configuration subspaces. Then, the robotic manipulations can be designed in the configuration subspaces. Finally, a typical industry application, fitting an eccentric crankshaft into a bearing hole of the automotive air‐conditioners, is used to validate the presented strategy.

The attractive region constructed in the configuration space has been applied to guide the robotic manipulations, such as, the locating and the insertion.

The designed robotic assembly system without using force sensor or flexible wrist has an advantage in terms of expense and durability for the automotive air‐conditioners manufacturing industry.

Most previous work on sensorless manipulation strategy has concentrated on inserting a symmetric peg into a hole. However, for the assembly of an eccentric peg into a hole, the robotic manipulations should be explored in a high‐dimensional configuration space as the six‐DOFs of the eccentric peg. In this paper, the decomposition method of the high‐dimensional configuration space would make the system analysis visible; then, the assembly strategy can be easily designed in the two subspaces.

To design a reconfigureable flexible fixture for the assembly of a set of sheet metal automotive body parts. Reconfigureable fixturing permits different parts to be grasped for assembly by a fixture without the need to conduct costly redesign and fabrication of hardware fixtures, which is an industry standard in widespread use in industry. While somewhat more complex than fixtures in current use, reconfigureable fixtures provide one solution to the problem of costly redesign of fixtures due to changes in dimensions, or geometry of parts to be assembled.

We propose a novel reconfigureable fixture for robotic assembly of a number of different parts. Motivated by the marine organism, O. vulgaris, commonly referred to as an octopus, which grasps different objects or prey using suction cups, the proposed fixture has three fingers, each equipped with a suction cup, to facilitate the grasping process and increase grasp flexibility. Using this design approach, the fixture is sufficiently general in design to grasp several different parts. To position the suction cups located on the flexible fixture, two linkage‐based mechanisms are employed. Pneumatic cylinders and electric motors are used as actuators. A prototype flexible fixture has been built and experimental results with this prototype confirm the effectiveness of the proposed flexible fixture. Software has been developed to calculate the relative positions and angles in the mechanism as required for reconfiguration.

The proposed reconfigureable fixture, used as an end‐of‐arm tool, permits each of a set of four sheet metal parts to be successfully grasped permitting assembly of these four components, in a robotic assembly work cell.

The proposed flexible fixture is a simple proof‐of‐concept device that is suitable for a laboratory setting. We do not consider part localization of parts when grasped by the reconfigureable fixture.

Assembly operations, in industrial manufacturing operations, are typically heavily reliant on hardware fixtures devices to orient and clamp parts together during assembly operations. While of great importance in such operations, hardware fixtures are very costly to design and build. Further, fixtures are designed for use with parts of specific dimensions and geometry, hence cannot be used to grasp or orient parts with even very small differences in dimensions or geometry. Typically, if parts with different dimensions or geometry are to be assembled, new hardware fixtures must be designed and manufactured to grasp and orient these parts. This lack of flexibility leads to substantial manufacturing costs associated with fixturing. Reconfigureable fixtures permit parts with different geometries to be grasped and oriented for assembly.

Reconfigureable fixtures for use in the automotive manufacturing sector is an important development due to the highly competitive nature of this industry. Rapid introduction of new models of vehicles is greatly facilitated through the use of reconfigureable fixtures which can be reprogrammed to grasp parts of different geometries required for new vehicle models.

This purpose of this paper is to design a peg-in-hole controller for a cable-driven serial robot with compliant wrist (CDSR-CW) using cable tensions and joint positions. The peg is connected to the robot link through a CW. It is required that the controller does not rely on any external sensors such as 6-axis wrist force/torque (F/T) sensor, and only the compliance matrix’s estimated value of the CW is known.

First, the peg-in-hole assembly system based on a CDSR-CW is analyzed. Second, a characterization algorithm using micro cable tensions and joint positions to express the elastic F/T at the CW is established. Next, under the premise of only knowing the compliance matrix’s estimate, a peg-in-hole controller based on force/position hybrid control is proposed.

The experiment results show that the plug contact F/T can be tracked well. This verifies the validity and correctness of the characterization algorithm and peg-in-hole controller for CDSR-CWs in this paper.

First, to the authors’ knowledge, there is no relevant work about the peg-in-hole assembly task using a CDSR-CW. Besides, the proposed characterization algorithm for the elastic F/T makes the peg-in-hole controller get rid of the dependence on the F/T sensor, which expands the application scenarios of the peg-in-hole controller. Finally, the controller does not require an accurate compliance matrix, which also increases its applicability.

The purpose of this paper is to describe a calibration method developed to improve the accuracy of a six degrees-of-freedom medical robot. The proposed calibration approach aims to enhance the robot’s accuracy in a specific target workspace. A comparison of five observability indices is also done to choose the most appropriate calibration robot configurations.

The calibration method is based on the forward kinematic approach, which uses a nonlinear optimization model. The used experimental data are 84 end-effector positions, which are measured using a laser tracker. The calibration configurations are chosen through an observability analysis, while the validation after calibration is carried out in 336 positions within the target workspace.

Simulations allowed finding the most appropriate observability index for choosing the optimal calibration configurations. They also showed the ability of our calibration model to identify most of the considered robot’s parameters, despite measurement errors. Experimental tests confirmed the simulation findings and showed that the robot’s mean position error is reduced from 3.992 mm before calibration to 0.387 mm after, and the maximum error is reduced from 5.957 to 0.851 mm.

This paper presents a calibration method which makes it possible to accurately identify the kinematic errors for a novel medical robot. In addition, this paper presents a comparison between the five observability indices proposed in the literature. The proposed method might be applied to any industrial or medical robot similar to the robot studied in this paper.

The purpose of this paper is to report research which led to the realization of a robot for miniaturized assembly endowed with high‐accuracy and high‐operative flexibility.

The proposed solution is a microassembly system composed of a Cartesian parallel robot with flexure revolute joints and a modular gripper with metamorphic fingertips, capable of adapting their shape to different micro‐objects. The fingertips are realized by electro‐discharge machining from a sheet of superelastic alloy. Thanks to its modularity, the gripper can be arranged with two opposite fingers or three fingers placed at 120°. The fingers are actuated by a piezoelectric linear motor with nanometric accuracy.

The experimental results on the prototype are very interesting. The measured positioning accuracy of the linear motors is 0.5 μm; the end‐effector positioning accuracy is lower, due to the non‐perfect kinematics and hysteresis of the flexure joints; however, these effects can be compensated by the direct measurement of the end effector position or by visual feedback. The metamorphic design of the fingertips remarkably increases the grasping force; moreover, the grasping is more stable and reliable.

The introduction of this microassembly system can fulfil the needs of a wide range of industrial applications, thanks to its accurate positioning in a relatively large workspace. The cost of the machine is relatively low, thanks to its modularity.

The combination of Cartesian parallel kinematics, cog‐free linear motors and superelastic flexure revolute joints allows one to obtain high‐positioning accuracy; the metamorphic fingertips enhance the grasping effectiveness and flexibility.

Aircraft structures are mainly connected by riveting joints, whose quality and mechanical performance are directly determined by vertical accuracy of riveting holes. This paper proposed a combined vertical accuracy compensation method for drilling and riveting of aircraft panels with great variable curvatures.

The vertical accuracy compensation method combines online and offline compensation categories in a robot riveting and drilling system. The former category based on laser ranging is aimed to correct the vertical error between actual and theoretical riveting positions, and the latter based on model curvature is used to correct the vertical error caused by the approximate plane fitting in variable-curvature panels.

The vertical accuracy compensation method is applied in an automatic robot drilling and riveting system. The result reveals that the vertical accuracy error of drilling and riveting is within 0.4°, which meets the requirements of the vertical accuracy in aircraft assembly.

The proposed method is suitable for improving the vertical accuracy of drilling and riveting on panels or skins of aerospace products with great variable curvatures without introducing extra measuring sensors.

The purpose of this paper is to analyse teleoperation of an ABB industrial robot with an ABB IRC5 controller. A method to improve motion smoothness and decrease latency using the existing ABB IRC5 robot controller without access to any low-level interface is proposed.

The proposed control algorithm includes a high-level proportional-integral-derivative controller (PID) controller used to dynamically generate reference velocities for different travel ranges of the tool centre point (TCP) of the robot. Communication with the ABB IRC5 controller was performed utilising the ABB PC software development kit. The multitasking feature of the IRC5 controller was used to enhance the communication frequency between the controller and the remote application. Trajectory tracking experiments of a pre-defined three-dimensional trajectory were carried out and the benefits of the proposed algorithm were demonstrated. The robot was intentionally installed on a wobbly table and its vibrations were recorded using a six-degrees-of-freedom force/torque sensor fitted to the tool mounting interface of the robot. The robot vibrations were used as a measure of the smoothness of the tracking movements.

A communication rate of up to 250 Hz between the computer and the controller was established using C# .Net. Experimental results demonstrating the robot TCP, tracking errors and robot vibrations for different control approaches were provided and analysed. It was demonstrated that the proposed approach results in the smoothest motion with tracking errors of < 0.2 mm.

The proposed approach may be employed to produce smooth motion for a remotely operated ABB industrial robot with the existing ABB IRC5 controller. However, to achieve high-bandwidth path following, the inherent latency of the controller must be overcome, for example by utilising a low-level interface. It is particularly useful for applications including a large number of short manipulation segments, which is typical in teleoperation applications.

Using the proposed technique, off-the-shelf industrial robots can be used for research and industrial applications where remote control is required.

Although low-level control interface for industrial robots seems to be the ideal long-term solution for teleoperation applications, the proposed remote control technique allows out-of-the-box ABB industrial robots with IRC5 controllers to achieve high efficiency and manipulation smoothness without requirements of any low-level programming interface.

Increasingly, the laborious task of removing burrs on castings is being automated with the introduction of robots. This is largely to ensure higher level of consistency and efficiency generally not possible with manual fettling. These burrs are unpredictable in size and shape, and if not removed, can lead to major problems in automated factory lines. Fettling is an important area in advanced robotic applications. This paper presents a strategy using a compliant wrist unit to obtain forces during robotic fettling. A specialised fettling wrist unit incorporating a remote centre of compliance (RCC) unit and a CCD camera is described. Experiments are carried out to evaluate the feasibility of this method. Fettling experiments are also performed using a force/torque sensing unit. A comparison of the results of these experiments is provided. The process parameters for fettling are described and relationships among these are established.

This paper aims to present design and characterization of a micrograsping system which is capable of safely grasping micro‐objects.

The proposed micrograsping system consists of novel MEMS based microgripper integrated with capacitive contact sensor (fabricated in standard micromachining process SOI‐MUMPs), sense electronics, a controller, high voltage actuation circuit and graphical user interface.

Due to the improvement in the lateral comb‐drive design, the actuator requires low actuation voltages in the range of 0‐45 V. This requires a simple and low power actuation circuitry. Capacitive feedback control mechanism is used in the sensor to detect the contact between the jaws and micro‐object while providing high values of the capacitance.

The designed sense electronics can sense the capacitance ranging from 0‐330 fF. Due to the availability of integrated contact sensor, objects ranging from 54 μm to 70 μm can be gripped safely with the applied maximum force of 220 μN at the tip of the gripper.

The performance of the microgripper, controller algorithm and associated electronics were experimentally quantified through the gripping of 65 μm sized human hair.