Beyond the Grip: A Universal Robotic End-Effector for Complex Tasks

Author: Denis Avetisyan


Researchers have developed a new end-effector that combines suction and grasping, enabling robots to handle a wider range of objects and perform more intricate manipulation tasks.

The visualization details how a robotic system executes primary actions-grasping (green), suction (purple), and lifting/pushing (blue)-across diverse tasks within the VacuumVLA environment, alongside corresponding object types (yellow), thereby illuminating the temporal interplay between action and object manipulation.
The visualization details how a robotic system executes primary actions-grasping (green), suction (purple), and lifting/pushing (blue)-across diverse tasks within the VacuumVLA environment, alongside corresponding object types (yellow), thereby illuminating the temporal interplay between action and object manipulation.

This work presents VacuumVLA, a unified suction and gripping tool integrated with Vision-Language-Action models to enhance robotic dexterity and manipulation capabilities.

Despite advances in robotic manipulation driven by Vision-Language-Action (VLA) models, current systems remain limited by the capabilities of standard two-finger grippers. This paper introduces ‘VacuumVLA: Boosting VLA Capabilities via a Unified Suction and Gripping Tool for Complex Robotic Manipulation’, presenting a novel end-effector integrating both suction and grasping modalities within a single, low-cost design. Experimental validation within state-of-the-art VLA frameworks demonstrates successful completion of complex tasks previously infeasible with conventional grippers. Could this hybrid approach unlock a new era of versatile and robust robotic manipulation in unstructured environments?


The Challenge of Robust Robotic Manipulation

Historically, robotic manipulation has been deeply rooted in meticulously crafted models of both the robot itself and its environment. This approach demands precise programming for every conceivable action and relies on the assumption that the world will conform to these pre-defined expectations. However, such systems falter when confronted with even slight deviations from the modeled reality – a misplaced object, unexpected lighting, or a novel task. The inherent rigidity stems from the difficulty in accounting for the infinite variability of real-world scenarios, effectively creating robots that excel in controlled laboratory settings but struggle with the dynamic and unpredictable nature of everyday life. This reliance on pre-programming severely limits a robot’s ability to generalize its skills, hindering its deployment in truly adaptable and useful applications.

Robotic systems frequently demonstrate impressive capabilities within controlled simulations, yet often falter when deployed in real-world settings-a phenomenon known as the “sim-to-real” gap. This discrepancy arises from the inherent difficulty in modeling the complexities of unstructured environments, where lighting, textures, and unforeseen obstacles differ drastically from their simulated counterparts. Furthermore, real-world physics is continuous and imperfect, while simulations rely on discrete approximations, leading to errors in force estimation and object interaction. Consequently, even seemingly minor discrepancies can accumulate, causing robots to misinterpret sensor data, execute actions incorrectly, and ultimately fail to generalize learned behaviors to novel situations. Addressing this challenge requires advancements in robust perception, adaptive control algorithms, and techniques for bridging the gap between simulated training and real-world deployment, ensuring robots can operate reliably and effectively beyond the confines of the laboratory.

The ability for robots to reliably manipulate objects in the real world is fundamentally hampered by the difficulty of bridging the gap between seeing and acting. Current systems often treat visual perception and action planning as separate modules, creating a bottleneck where interpreted visual data must be painstakingly translated into precise motor commands. This process struggles with the inherent ambiguity of real-world scenes – variations in lighting, partial occlusions, and unexpected object configurations all introduce uncertainty. More sophisticated approaches require robots to not simply recognize objects, but to understand their affordances – what actions are possible with them – and to dynamically adjust plans based on ongoing visual feedback. Effectively integrating these processes, allowing for nuanced and adaptive action based on continuous perception, remains a central challenge in achieving truly generalizable robotic manipulation.

The robotic hand utilizes adjustable grip width to handle objects of different sizes, alongside three standard two-finger gripper actions.
The robotic hand utilizes adjustable grip width to handle objects of different sizes, alongside three standard two-finger gripper actions.

Vision-Language Models: A Foundation for Intuitive Control

Vision-Language Models (VLMs) represent a significant advancement in robotic control by bridging the gap between human instruction and robotic action. These models are trained on extensive datasets of paired visual and textual data, allowing them to establish correlations between language and visual features. Consequently, VLMs can process natural language commands – such as “pick up the red block” – and simultaneously analyze visual input from cameras or other sensors to understand the environment. This capability enables robots to interpret instructions in a human-understandable format and translate them into appropriate actions, without requiring explicitly programmed routines for each task or environment. The models achieve this through techniques like attention mechanisms, which allow the robot to focus on relevant visual elements corresponding to specific words in the instruction, thereby grounding the language in the observed scene.

Current robotic frameworks, such as π0 and DexVLA, utilize Vision-Language Models (VLMs) as a core component for translating human instructions into executable robot actions. These systems ingest both visual input, typically from onboard cameras, and natural language commands. The VLM processes this multimodal data to generate a representation of the desired task, which is then decoded into specific robot control signals. π0 employs a direct mapping from the VLM’s output to robot joint velocities, while DexVLA uses the VLM output as input to a more complex action decoding process, allowing for greater control and task generalization. Both frameworks demonstrate the feasibility of using VLMs to bridge the semantic gap between human intention and robotic execution, enabling robots to respond to instructions described in natural language while simultaneously interpreting their visual surroundings.

Flow matching is a probabilistic modeling technique used to accelerate the decoding of robot actions from visual and linguistic inputs. Unlike traditional diffusion models which require numerous iterative denoising steps, flow matching learns a continuous normalizing flow that directly transforms noise into desired actions. This allows frameworks like π0 and DexVLA to generate robot actions significantly faster, reducing the computational burden and latency associated with action planning. Specifically, by training a vector field that guides the action distribution towards the target, flow matching enables single-step decoding, resulting in more efficient and real-time robot control compared to iterative approaches. The technique’s ability to model complex, multi-modal action distributions also contributes to improved accuracy and robustness in robotic task execution.

DexVLA improves robotic control through the implementation of an ‘Action Expert’ module, a secondary vision-language model specifically trained to refine proposed robot actions. This module operates by receiving both the visual observation and language instruction, as well as the initial action predicted by the primary VLM. The Action Expert then generates a residual correction to this initial action, effectively acting as a discriminator to improve the quality and accuracy of the final robotic movement. This approach allows DexVLA to benefit from the strengths of both the primary VLM for broad action space coverage and the Action Expert for detailed, nuanced control, leading to more reliable task completion.

VacuumVLA builds upon the DexVLA architecture to enable vacuum-based manipulation.
VacuumVLA builds upon the DexVLA architecture to enable vacuum-based manipulation.

A Hybrid End Effector: Expanding the Range of Robotic Grasping

Traditional robotic grippers, specifically single-function designs such as parallel jaw grippers and vacuum suction grippers, exhibit limitations when handling objects with varied geometries and material properties. Parallel jaw grippers require unobstructed access to an object’s lateral surfaces for a secure grasp and struggle with delicate or irregularly shaped items. Vacuum suction grippers, while effective on smooth, non-porous surfaces, are unreliable with textured, porous, or curved objects due to insufficient sealing. These limitations result in decreased manipulation success rates and necessitate frequent intervention in unstructured environments where object characteristics are unpredictable, highlighting the need for more versatile end-effector designs.

The Hybrid End Effector addresses limitations of single-function grippers by integrating both parallel jaw and vacuum suction capabilities into a single device. This design leverages the secure and reliable grasping of parallel jaws for objects with well-defined surfaces, while simultaneously utilizing vacuum suction to handle objects with irregular shapes, delicate surfaces, or those requiring a more adaptable grasp. The combination allows for manipulation of a broader range of objects than either mechanism could achieve independently, improving operational flexibility and reducing the need for frequent tool changes in robotic applications. This multi-functional approach enhances the robot’s ability to adapt to varying object geometries and material properties within a single task.

The implementation of a hybrid end effector expands robotic grasping capabilities by addressing limitations inherent in single-function grippers. Traditional grippers, such as parallel jaw or vacuum-based systems, often fail when presented with objects possessing irregular geometries, varying surface textures, or fragile compositions. By combining the mechanical compliance of a parallel jaw gripper with the adaptive surface contact of vacuum suction, the hybrid approach allows for secure grasping of a wider variety of objects. This broadened compatibility directly translates to improved robustness in manipulation tasks, particularly in unstructured or dynamic environments where object presentation is unpredictable, as demonstrated by success rates of 86.7% with DexVLA and 73.3% with π0 when performing object placement.

The VacuumVLA implementation demonstrates the efficacy of the Hybrid End Effector when paired with existing robotic frameworks. Testing involved a tray-placement task, where VacuumVLA achieved an 86.7% success rate when integrated with the DexVLA framework. Performance decreased to 73.3% success when VacuumVLA was used with the π0 framework. These results indicate a substantial improvement in object manipulation capabilities compared to single-function end effectors and highlight the framework-dependent performance of the system.

The end-effector features an integrated gripper and suction cup for versatile object manipulation.
The end-effector features an integrated gripper and suction cup for versatile object manipulation.

Towards Adaptable Robotics: Validation and Future Directions

Recent advancements in adaptive robotics demonstrate substantial gains in manipulation success through the implementation of subtask planning. Specifically, the VacuumVLA system, leveraging this approach, has exhibited markedly improved performance across diverse object manipulation tasks. Evaluations reveal that DexVLA, a component of VacuumVLA, achieved a 73.3% success rate in complex actions like opening containers and precisely placing objects. This represents a significant increase over the 66.7% success rate attained by the π0 system under identical conditions, highlighting the efficacy of guided subtask planning in enhancing robotic dexterity and reliability. These results suggest a pathway towards robots capable of more effectively interacting with and manipulating objects in real-world, unstructured environments.

To address the challenges of transferring robotic skills from simulated environments to the complexities of the real world, researchers employed teleoperation as a crucial data collection method. This approach involved human operators directly controlling the robot to perform tasks, generating data that captured the nuances of real-world interactions – data that is difficult to replicate in simulation alone. The resulting dataset was then used to refine the VacuumVLA and π0 algorithms, effectively bridging the “sim-to-real gap” and improving their performance on physical tasks. By learning from human demonstrations, the robots were able to adapt to unpredictable conditions and achieve more reliable manipulation success, demonstrating the power of combining human expertise with robotic automation.

Evaluations of the robotic systems on a capping task revealed notable differences in precision. DexVLA demonstrated an average precision of 5.3 centimeters when attempting to securely close containers, indicating a reasonable level of control and accuracy in its movements. In comparison, π0 achieved a higher degree of precision, registering 3.1 centimeters. This suggests that, while both systems successfully completed the capping task, π0 exhibited finer motor control and a greater ability to consistently align and fasten the caps, highlighting a potential advantage in tasks demanding meticulousness and repeatability.

The development of VacuumVLA and its demonstrated success in complex manipulation tasks represents a significant step toward robots capable of thriving in real-world, unstructured settings. Previous robotic systems often struggled with the variability inherent in unconstrained environments, requiring extensive reprogramming for even minor changes in object position or type. However, this research highlights a path toward greater adaptability, where robots leverage subtask planning and refined learning techniques-bridging the gap between simulation and reality through teleoperation-to handle unforeseen circumstances. This newfound versatility promises to unlock applications ranging from automated assistance in homes and hospitals to efficient operation in warehouses and disaster relief scenarios, ultimately enabling robots to move beyond highly controlled settings and become truly integrated into the complexities of everyday life.

Continued development in adaptive robotics necessitates a broadened operational capacity, moving beyond current task limitations to encompass a wider array of real-world challenges. Researchers are actively pursuing strategies to enhance a robot’s ability to generalize – to perform effectively in previously unseen environments and with unfamiliar objects – which requires advancements in both learning algorithms and data representation. Crucially, these efforts are tightly coupled with the refinement of perception systems; creating algorithms capable of reliably interpreting complex, noisy sensory data is paramount to enabling robust robotic manipulation and navigation in unstructured settings. Progress in these areas promises to unlock the full potential of adaptable robots, allowing them to function with greater autonomy and efficiency across diverse applications.

Data was collected using a foot-operated USB device to control a suction cup in a homogeneous teleoperation setup.
Data was collected using a foot-operated USB device to control a suction cup in a homogeneous teleoperation setup.

The development detailed within this research exemplifies a commitment to elegant solutions. The unification of suction and grasping into a single end-effector, guided by Vision-Language-Action models, isn’t simply additive complexity; it’s a refinement of robotic capability. It recalls the sentiment of Carl Friedrich Gauss: “If I have seen further it is by standing on the shoulders of giants.” This work doesn’t reinvent robotic manipulation from scratch, but rather builds upon existing foundations – the established principles of gripping and suction – to achieve a new level of dexterity. The core concept of integrating these capabilities into a unified system underscores a preference for streamlining, reducing the need for multiple tools and simplifying the overall robotic workflow. It’s a demonstration of how focused design can unlock previously unattainable results.

Beyond the Grip

The unification of suction and grasping, as demonstrated, is not an endpoint, but a distillation. The current work addresses a practical limitation-the brittle specialization of end-effectors-but invites consideration of the underlying fragility of action itself. The reliance on Vision-Language-Action models, while effective, merely externalizes the problem of robust perception and control. Future iterations should not seek increasingly elaborate multimodal input, but rather, a parsimonious representation of essential affordances. The true challenge lies not in teaching a robot what to do, but in enabling it to discern whether to do anything at all.

A critical limitation remains the assumption of a static environment. Real-world complexity introduces dynamic occlusions, unpredictable material properties, and the ever-present potential for catastrophic failure. The next phase necessitates a shift from reactive adaptation to anticipatory resilience-a system that anticipates disturbance, not merely responds to it. This demands a fundamental re-evaluation of reward functions, moving beyond task completion to embrace the elegance of minimal intervention.

Ultimately, the pursuit of “dexterous robotics” is a misnomer. True intelligence does not reside in the multiplicity of possible actions, but in the wisdom to refrain from most of them. The ideal end-effector, therefore, may be one that minimizes its own presence-a system so attuned to its environment that it acts only when absolutely necessary, disappearing into the background of its own success.


Original article: https://arxiv.org/pdf/2511.21557.pdf

Contact the author: https://www.linkedin.com/in/avetisyan/

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2025-11-28 06:34