Speed and Separation Monitoring (SSM) according to ISO 10218 requires continuous distance monitoring, bounded reaction times, and maintenance of a protective separation distance under worst-case conditions. While certified SSM implementations predominantly rely on exo-centric safety scanners or external vision systems, robot-mounted ego-centric sensing architectures remain under-investigated with respect to normative SSM requirements. A feasibility study of ego-centric Time-of-Flight sensor rings for robot-mounted workspace monitoring is presented. An 18-sensor VL53L7CX ring system mounted on a cobot is analyzed through a structured decomposition of the reaction-time chain and an estimation of the resulting protective separation distance based on a conservative normative framework. The evaluation yields a protective separation distance of approximately 2.4 m under conservative ISO 10218-2 assumptions. For the evaluated architecture, this indicates that standalone SSM is not suitable for close-range collaborative operation. This result should not be interpreted as a fundamental limitation of ego-centric perception itself. Rather, the findings suggest that ego-centric sensing is more appropriately understood as a complementary sensing component within combined collaborative safety concepts. In this role, it can support localized near-workspace monitoring and the detection of human approach in the immediate vicinity of the robot, while overall interaction safety remains governed by additional protective measures.

This paper proposes an optimal control approach to reduce frame vibrations in robotic pick and place tasks, caused by rapid acceleration and deceleration of the robot. The objective of the proposed optimal control approach is to determine time-optimal trajectories that cancel out residual frame vibrations after trajectory execution. The control problem is defined for a delta robot but can be adapted to any type of robot used for pick and place tasks. To solve the optimal control problem numerically, it is transformed into a nonlinear programming problem using the Legendre-Gauss-Lobatto collocation method. To validate the approach, experiments are conducted to compare the residual frame vibrations of optimized trajectories with typical pick and place trajectories. The novelty of the paper is the vibration reduction with an optimization-based approach on a complex multi-degree-of-freedom robot system whose dynamic parameters are identified with experimental data. In addition, a mathematical description of all constraints required for a robotic pick and place task is proposed for the optimization.

In Robot-Assisted Multidirectional Additive Manufacturing (RAM-AM), the travel paths (non-printing transitions) between separate printing segments are rarely planned explicitly. This often results in discontinuities, inefficient connections, and severe collision risks, particularly in moving-bed configurations where the entire part moves relative to the nozzle. We propose a decoupled planning pipeline that first computes a safe, smooth geometric path in the platform frame and subsequently generates an executable joint-space trajectory under kinematic limits. The geometric planning utilizes an A* search on an OctoMap-based voxel grid with an asymmetric layered cost map to actively steer the end-effector away from the printed structure. This raw path is smoothed using sparse B-splines, and orientations are optimized by blending Spherical Linear Interpolation (Slerp) with Artificial Potential Fields (APF) to maximize clearance. For trajectory generation, we resolve kinematic redundancy by sampling pose tolerances and selecting a globally consistent joint sequence via second-order Dynamic Programming (DP), explicitly penalizing joint jerks and singularities. Validated on a 6-DoF KUKA KR6 R900 sixx, the method is demonstrated in scenarios involving complex obstacles like holes. Results show that our approach guarantees safe obstacle avoidance where standard baselines fail, yields significantly smoother motions, and that exploiting the redundant rotation about the extrusion axis drastically reduces the inverse kinematics search effort.

Collaborative robots (Cobots) are increasingly being used as assistance systems to relieve humans in private and commercial environments. Current systems are designed to stop in the event of a collision, which means that robots only stop after unwanted contact. For completely safe physical collaboration, collisions should be avoided as far as practicable, and distance measurement should take place instead. The internal sensors of Cobots typically do not provide exteroceptive distance measurement, which is why additional sensors must be added. To ensure safe collision avoidance, low-latency systems are required to monitor the work area and avoid collisions. This work investigates how different integration methods for distance-sensors in ROS2 affect end-to-end latency when running on a resource-constrained microcontroller. A Raspberry Pi Pico is used to connect two low-cost sensors that are representative of typical HRC cells: an ultrasonic-sensor and a time-of-flight-sensor. Both sensors use different communication standards. Two integration strategies are compared. In the standard ROS2 integration, the sensor firmware runs on the microcontroller, which streams the data via a serial connection to a ROS2 node. In the micro-ROS-based integration, the firmware and ROS2 publisher are combined in a single application. For each sensor, the latency between measurement acquisition and publication in a ROS2 topic is quantified over multiple trials. The results show that micro-ROS reduces average latency and suppresses extreme outliers, although the overall update rate remains limited by the sensor’s intrinsic sampling frequency. The study derives practical design guidelines for latency-aware integration in ROS2 on low-cost microcontrollers and discusses their implications for safe HRC.

Interactive mechanism design benefits from continuous parameter variation with immediate kinematic and kinetostatic feedback. However, existing interactive workflows often couple variables ad hoc and lack robust dependency management, which can yield ambiguous update order and inconsistent model states under circular relations. It is hypothesized that making dependencies explicit and validating updates transactionally can preserve a consistent model state while maintaining interactive latency. This paper extends Mechanism Developer (MechDev) with a unified workflow that combines slider-based parametrization for real-time exploration with a graph-based phrasing interface for defining algebraic relations among variables. Updates are compiled into a dependency graph and must pass a transactional validation pipeline (syntax, binding, safety, cycle detection to enforce a directed acyclic graph (DAG)) before commitment. For accepted updates, dependent variables are propagated in deterministic topological order and applied to the live mechanism model and views. In two planar linkage case studies (four-bar and five-bar), the system deterministically propagates parameter changes and rejects invalid or cyclic definitions without corrupting the model state. These results indicate that dependency-graph-based phrasing enables robust, real-time parameter coupling for interactive mechanism design within MechDev.

I2C is widely used in mechatronic systems due to its low wiring effort and broad component interoperability. When identical sensors provide fixed or only weakly configurable addresses, shared-bus integration is limited by address conflicts, cumulative capacitive loading, and sequential transaction timing. These constraints limit the scalability and predictability of multi-sensor architectures. This work presents a segmented I2C architecture that enables the deterministic replication of identical sensor modules through controlled bus visibility. Modular piggyboards implement electrically isolated downstream branches connected to a shared main bus. A safe-channel startup strategy ensures reproducible enumeration before downstream devices become visible. A circular multi-sensor array based on VL53L7CX time-of-flight (ToF) sensors was implemented to evaluate scalability and acquisition behavior. Experimental results demonstrate bounded and reproducible startup behavior and cycle-time jitter, and sustained multi-sensor operation without additional runtime penalty compared to direct bus wiring. The approach establishes a modular scaling principle for I2C-based sensor arrays in mechatronic systems while preserving standard bus compatibility.

Thumb degree-of-freedom (DOF) allocation in anthropomorphic robot hands involves a trade-off between functional mobility and mechanical-control complexity. This study presents a controlled multi-metric framework for comparing recurring thumb DOF configurations under common palm geometry, non-thumb finger structure, reference frames, Denavit-Hartenberg kinematics, and sampling assumptions. Five literature-derived thumb configurations, namely 3-1-1, 2-2-1, 2-1-1, 2-0-1, and 1-1-1, were evaluated to determine which thumb DOFs should be preserved when kinematic complexity is reduced. The theoretical evaluation included Kapandji Opposition Test reachability, opposition alignment, workspace volume, workspace compactness, cylindrical grasp opportunity, and Jacobian-based dexterity. A targeted experimental validation of the 2-1-1 and 2-0-1 prototypes was then performed on a tendon-driven test bench. The results showed that qualitatively similar thumb configurations are quantitatively unequal: several designs achieved identical Kapandji scores but differed substantially in workspace, alignment, dexterity, and grasp feasibility. Overall, 3-1-1 achieved the strongest overall capability, while 2-2-1 emerged as the strongest reduced-complexity alternative and achieved the best mean dexterity. Retaining two active carpometacarpal DOFs preserved a large share of dexterous function, whereas metacarpophalangeal fixation maintained selected cylindrical grasps but narrowed the feasible task boundary.

The mechanical design of anthropomorphic robot hands is complex and comprehensive and accessing relevant information remains challenging. Existing reviews provide valuable insights but lack a structured overview of the mechanical design approaches for robot hands. This work addresses this gap by introducing the Library of Approaches (LoA), a collection of mechanical design approaches for tendon-driven, rigid-sequential anthropomorphic robot hands, organized in morphological boxes. In a systematic mapping following the PRISMA guideline, joint-related design approaches are collected and used to synthesize initially undocumented principal solutions (PSs) for fields of interest (FoIs). Literature references are then categorized into the established PSs and assigned to different morphological boxes. To comprehensively capture the state of the art, five separate search strategies are conducted, resulting in the analysis of 147 publications, including 87 robot hands and 110 authors. In total, 92 FoIs and 177 PSs are identified. The main objective is to provide a convenient initial source of references for the early mechanical design of anthropomorphic robot hands, without claim of completeness. The study concludes with a discussion of current limitations and potential future work.

This contribution presents the concept of a Digital Tool Chain based on a thorough literature review. It combines the methods of mechanism synthesis, load analysis and structural optimization in a model-based systems approach and thus enables the development of dynamically more powerful and resource-efficient planar mechanisms in a significantly shorter development time. The novelty of this approach is the orchestration and connection of well-known computer-aided engineering tools.

Systematic design, development and applications of Compliant Grippers (CGs) have surged in the past decade. The works are diverse but information is dispersed. This paper provides a systematic review of 1009 peer reviewed manuscripts in the last ten years, sourced from the Scopus database. Keywords search on CG design, analytical methods, gripper size and design verification. 239 papers are mapped onto applications, types of workpieces, actuation technologies, focusing onto CG design methodologies. Actuation methods are classified into indirect and direct. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol is followed. Key findings include: (i) CGs are mostly designed with direct mechanical load actuation, the corresponding synthesis methods follow well defined processes; (ii) Most CGs cater to convex, regular and small objects; (iii) much focus on their application is on research and development followed by manufacturing and assembly, healthcare, electronics and semiconductors and food processing; (iv) fluidic actuation is gaining prominence but not as much as direct actuation; and (v) systematic synthesis methods are needed for other existing and emerging technologies like controlled adhesion, smart materials and jamming.

Due to the climate change, changing legislation and increased demands on energy efficiency, the industry is constantly looking for ways to minimize costs. Not only in the packaging industry, but also in the fields of handling and forming technology, non-uniformly translating mechanisms are used to generate certain motions. For several decades now, there have been attempts to operate such mechanisms in a more energy-efficient manner, with so-called eigenmotion being a promising approach. Practical implementation in industry has become possible with the development of servomotors, as they can reproduce the eigenmotion with high precision. The combination of non-uniformly translating mechanisms and a variable drive speed has been the subject of research ever since. The variation of the input speed of a mechanism results in a changed output speed. This article presents the development and the validation of a design method for energy-efficient cam mechanisms while maintaining the exact motion specification.

Growing interest in Humanoids calls for safe and cost-efficient robot hand designs. While current rigid-sequential robot hands achieve reliable grasping, the mechanical design is complex and tedious. Flexible tendon-driven hands offer a promising alternative but still fail to surpass rigid designs in terms of functionality and degrees of actuation. We propose the use of tendon-driven flexible fingers with helical tendon routing to maintain grasping performance while reducing design complexity and increasing passive safety. A developed mechanical prototype is successfully evaluated using the Kapandji test and Feix taxonomy. The design shows promise as an alternative to classical SRP designs, with future work addressing current limitations. Specifically, flexibility must be reduced to achieve greater stiffness for precision grasps, and a mathematical model of the hand must be derived to enable further evaluation of grasp point identification and fingertip forces. Literature on continuum robots offers potential approaches for both challenges.

This paper addresses the kinematic design of a steering mechanism adapted for a three-lane vehicle equipped with three rear steering wheels. Traditional Ackermann steering principles have been extended to accommodate the added complexity introduced by the third wheel. The third wheel increases the system’s design parameters, presenting challenges to the design process for linkage designs. In designing a six-bar linkage (WATT II mechanism), large-scale parameter variation was analyzed to identify the ideal steering relationship between the wheels and the influential parameters for this. The analysis revealed that asymmetric configurations improve alignment with the ideal Ackermann condition, achieving maximum deviations in the order of 𝒪(0.1 ^∘) for steering angles between -30^∘ and 30^∘ . The additional design parameters allow for a variety of parameter combinations that result in a very good representation of the Ackermann condition.

Delta robots are the most common parallel robots for manipulation tasks. In many industrial applications, they must be operated at reduced speed, or dwell times have to be included in the motion planning, to prevent frame vibrations. As a result, their full potential cannot be realized. Against this background, this publication is concerned with the mechanical design of an active dynamic balancing unit for the reduction of frame vibrations. In the first part of this publication, the main design requirements for an active dynamic balancing mechanism are discussed, followed by a presentation of possible mechanism designs. Subsequently, one the most promising mechanisms is described in detail and its kinematics and dynamics equations are derived. Finally, the dimensions of a prototype mechanism designed to experimentally validate the concept of active dynamic balancing are defined using the example of Suisui Bot, a low-cost Delta robot.

Im Rahmen dieses Beitrags soll die Idee einer digitalen Werkzeugkette vorgestellt werden, die die Methoden der Mechanismensynthese, Belastungsanalyse und Strukturoptimierung modellbasiert miteinander verbindet und es somit ermöglicht, in einer signifikant kürzeren Entwicklungszeit dynamisch leistungsfähigere bzw. ressourceneffizientere ebene Mechanismen zu entwickeln. Digital Tool Chain for Lightweight-optimized Design of High-speed, Planar Mechanisms. This contribution presents the idea of a digital tool chain that combines the methods of mechanics synthesis, load analysis and structural optimization in a model-based approach and thus enables the development of dynamically more powerful and resource-efficient planar mechanisms in a significantly shorter development time.

Due to the shortening of product life cycles, increased product variety and sinking product prices, it is of paramount importance for industries to deploy flexible and adaptive production solutions to increase their resilience. Robotic systems, which are capable of executing a broad range of tasks, play a crucial role in achieving such a resilience, and their application fields will expand even further. Particularly, mobile manipulators as a combination between mobile platforms and robotic arms ensure even greater flexibility with respect to robots which are not mounted over a mobile base due to their redundancy, which entails infinite possible ways to plan/execute a motion (kinematic redundancy), of integrating them in the industrial processes and of perceiving the surrounding environment (sensoric redundancy). In this paper such a redundancy is analyzed under a unified framework, where the mobile base is modeled with an equivalent serial kinematic structure and, consequently, the hybrid robot is considered as a serial redundant manipulator, named Redundant Hybrid Robot.

Compliant grippers hold great promise in improving precision and safety in minimally invasive surgery (MIS), offering versatile solutions for tissue manipulation while minimizing trauma. A novel focus on a capsule-shaped compliant gripper introduces innovative design methodologies, including shape optimization and consideration of axillary lymph node dimensions. By integrating compliant beams internally and optimizing their shape, this gripper offers enhanced precision and adaptability in tissue manipulation, addressing specific challenges in delicate surgical interventions such as lymph node dissection in breast cancer surgery. An isogeometric approach for the analysis of geometrically nonlinear beam structures enables a seamless integration of exact geometry in computer-aided design (CAD) into the analysis framework. It incorporates frictionless beam contact conditions based on a regularized penalty law, which enables an efficient and accurate simulation of the compliant grippers. Optimization results demonstrate the efficacy of the methodology, producing a compliant beam configuration that applies a mean pressure of 204.93 Pa, with a maximized contact area facilitating form closure gripping. Experimental validation using a test bench confirms the consistency of the contact areas predicted by simulations, with force sensor measurements showing good agreement with simulation results in most cases. Minor discrepancies, particularly in higher-pressure regions, are attributed to sensor limitations but do not significantly impact the overall findings. Continued research and refinement of these methodologies are essential for furthering the field of compliant gripper design and its application in medical and surgical contexts.

Am Institut für Getriebetechnik, Maschinendynamik und Robotik der RWTH Aachen wird seit einiger Zeit die Software „Mechanism Developer“ (MechDev) zur interaktiven Auslegung und Analyse von ebenen Getrieben entwickelt [1-2] und dessen aktuelle Fortschritte regelmäßig publiziert [3-5]. Diese Software ist ab sofort allgemein verfügbar und lizenzierbar. MechDev wird sowohl für Lehrzwecke als auch für industrielle Anwendungen empfohlen. Kern der Software ist ein leistungsfähiges Analysetool zur kinematischen und kinetostatischen Analyse ebener ungleichmäßig übersetzender Getriebe, welches ständig weiterentwickelt wird. The Software Mechanism Developer – now available for Education and Industry. The Institute of Mechanism Theory, Machine Dynamics and Robotics of RWTH Aachen University has been developing the Mechanism Developer (MechDev) software for the interactive design and analysis of planar transmissions for some time [1-2] and regularly publishes its current progress [3-5]. This software is now generally available to the public. MechDev is recommended for educational purposes as well as for industrial applications. The core features of the software constitute a powerful toolkit for the kinematic and kinetostatic analysis of planar linkages, which is constantly being improved on.