Rizon 4S
About
About Rizon 4S
Rizon 4S is Flexiv’s seven-axis adaptive robot configuration with an end-of-arm force/torque sensor. The 21 kg arm provides 919 mm reach and a 4 kg load rating that includes the 0.5 kg sensor. Force-sensing accuracy is specified at 0.03 N, distinct from its ±0.05 mm pose repeatability. The IP65 arm can mount in any orientation and operates from 0 to 45 °C.
Hesper control hardware and Flexiv Elements coordinate motion and force regulation for configured contact tasks. The current range page calls this configuration “Rizon 4 + F/T Sensor”, while the linked datasheet retains the Rizon 4s name. Research systems have paired it with different grippers and learned policies for conveyor sorting and precise assembly; those experiments depend on their particular tools, observations and controllers. Earlier brochures list a 959 mm reach for the previous specification.
Capabilities
Source-backed capabilities
- Operating environments: Laboratory conveyor pick-and-sort setup, Laboratory peg-in-hole fixtures, Laboratory contact-force test setup
- Control modes: Autonomous
- Pick and place
Research demonstration - Pick objects from a moving conveyor and sort them by colour in physical learned-policy trials. - environment: Laboratory conveyor pick-and-sort setup
Source - Precision insertion
Research demonstration - Insert 3D-printed pegs into matching holes using a simulated-training policy driven by joint and gripper state. - environment: Laboratory peg-in-hole fixtures
Source - Force-controlled manipulation
Research demonstration - Slide an end effector along a force scale while targeting 10 N normal force in physical policy evaluations. - environment: Laboratory contact-force test setup
Source
Observed use
Exact-product configurations are shown without inferring supply, purchase, customer status, standard fit, deployment or partnership.
- Robotiq 2F-85
Research Experiment - Mounted - Physical - The assembly experiments use a Flexiv Rizon 4S arm with a mounted Robotiq 2F-85 gripper.
Source - WUJI HAND 2
Research Experiment - Mounted - Physical - Industrial Next used Wuji Hand 2 on Flexiv Rizon 4S arms for conveyor pick-and-sort research. The right arm picked and sorted objects; the left remained static with an additional camera.
Source
Research
- Blind Precise Assembly: Proprioceptive Sim-to-Real Peg-in-Hole for Diverse Parts
2026-10-16 - Research Publication - This work trains contact-rich assembly policies using only proprioceptive joint histories. A policy trained entirely in simulation transfers to physical peg insertion without cameras, force sensing or real-world fine-tuning.
Source - ForceWAM: Decoupling Future and Response Learning from Demo and Play Data for Contact-Rich Manipulation
2026-10-13 - Research Publication - ForceWAM separates future prediction from force-aware response learning using task demonstrations and play data. Physical experiments on Flexiv Rizon 4S test contact-rich sliding, box flipping and Hanoi-ring manipulation.
Source - Getting Out and Getting Back: World and Behavior Grounding in Real2Sim2Real Co-Training
2026-09-30 - Research Publication - This Industrial Next and Cambridge study separates physical-world fidelity from human-motion fidelity in simulation co-training. A dual Flexiv Rizon 4S setup with Wuji Hand 2 performs conveyor pick-and-sort. For the 500M flow-matching policy, fully grounded co-training raises success from 26/50 to 43/50 trials; the study also evaluates post-trained foundation models.
Source
Resources
Curated durable documents and official technical references.
- Rizon adaptive robot datasheet
PDF · Rizon 4s / Rizon 4 + F/T sensor · Flexiv
Source - Historical Rizon product brochure
PDF · Earlier Rizon 4 and Rizon 4s specification · Flexiv
Source - Official robot description and URDF generation
WEB / CODE · Rizon4s · Flexiv Robotics
Source