Massimo Satler

Towards Smart Farming and Sustainable Agriculture with Drones

The use of drones in agriculture is becoming more and more popular. The paper presents a novel approach to distinguish between different fields plowing techniques by means of an RGB-D sensor. The presented system can be easily integrated in commercially available Unmanned Aerial Vehicles (UAVs). In order to successfully classify the plowing techniques, two different measurement algorithms have been developed. Experimental tests show that the proposed methodology is able to provide a good classification of the fields plowing depths.

Bilateral teleoperation under time-varying delay using wave variables

Any teleoperation system involving two distant devices is affected by communication delay due to the physical gap between the devices. Several approaches based on wave variables have already been proposed to deal with time-varying delay. However, these approaches are too conservative resulting in high degradation from the constant time delay case. In this paper, we propose a new control scheme for bilateral teleoperation under time-varying communication delay entirely developed in the wave variables domain. The proposed method minimizes the performance degradation from the constant time delay case. Experimental results show the validity of the proposed scheme.

MOTORE: A mobile haptic interface for neuro-rehabilitation

The present paper introduces a novel type of haptic interface which is fully portable and employs only onboard sensors and electronics to solve accurate localization and force feedback generation. The device offers 2DOF force control while sliding on a plane and maintaining its orientation comfortable for the user. The device generates force feedback information without any intermediate link between the motion wheels and the grasping handle. The device has been designed for application in neuro-rehabilitation protocols and it adopts specific mechanical, electrical and control solutions in order to cope with patient requirements. The paper describes the mechanical and electronic solutions as well as the most relevant features of control implementation issues that were addressed in the system design.

Performance Indices and Tuning in Process Control

Industrial practice in process control shows a very wide gap with respect to the theory, as usually taught at the university. Standard controller tuning is often a compromise between performance and robustness. In this paper we examine some common PI(D) controller tuning rules and the achievable performances for a PI(D) controlled plant modeled as a first order plus time delay. The performance indices considered are IAE and ISE in a particular non-dimensional form including also controller output variations. The output performance indices are weakly dependent on loop gain. Therefore loop gain is essentially constrained by robustness, while the indices are dominated by the frequency response. Conversely the controller output variations are strongly dependent on the loop gain

Control of a desktop mobile haptic interface

Most haptic devices share two main limits: they are grounded and they have limited workspace. A possible solution is to create haptic interfaces by combining mobile robots and standard grounded force-feedback devices, the so called Mobile Haptic Interfaces (MHIs). However, MHIs are characterized by dynamical limitations due to performance of the employed devices.

Towards an autonomous flying robot for inspections in open and constrained spaces

A Micro Aerial Vehicle (MAV) capable of navigating in outdoor environments by means of proprioceptive data fusion techniques as well as in indoor and particularly in constrained spaces is here presented. The aim of this system is to inspect failures or procedures correctness inside dangerous areas where human presence should be avoided for long or short time periods. This solution has been oriented toward the specific context of visual inspection of industrial area and it has been tested in a laboratory testbed. In this paper we present hardware and software development of a MAV that can reliably navigate both in outdoor and indoor scenarios making it possible to autonomously change the working location.

Stacked generalization for scene analysis and object recognition

The problem of object recognition and detection has been largely addressed by the robotics community, since its importance both in mapping and manipulation problems. One possible approach for the recognition task is to assume a specific a-priori knowledge of the objects possibly present in a scene. In this framework, this paper presents a novel technique for object detection and recognition based on Stacked Generalization (SG) method developed by Wolpert in 1992. The innovation of the proposed technique is the introduction of SG classification method to perform a multi-layer object recognition fusing heterogeneous spatial and color data acquired with an RGB-D camera. To improve the accuracy and the robustness of the system to environmental variability, we introduce a second layer classifier. Its goal is to evaluate and weights the results of the first layer classifiers, thus combining and improving the overall classification performance. This technique has a low computational cost and is suitable for on-line applications, such as robotic manipulation or automated logistic systems. To validate the presented approach experimental tests have been carried out and results are reported.

Portable Haptic Interface with Omni-Directional Movement and Force Capability

We describe the design of a new mobile haptic interface that employs wheels for force rendering. The interface, consisting of an omni-directional Killough type platform, provides 2DOF force feedback with different control modalities. The system autonomously performs sensor fusion for localization and force rendering. This paper explains the relevant choices concerning the functional aspects, the control design, the mechanical and electronic solution. Experimental results for force feedback characterization are reported.

Energy recovery in time-varying delay teleoperated system using wave-variables

While control theory for bilateral teleoperation systems under constant time communication delay is well developed, the research on time-varying communication delay systems is still ongoing. Most wave-based approaches proposed in literature to deal with time-varying delay appear too conservative resulting in high degradation from the constant time delay case. We have already proposed a bilateral control scheme with energy balance monitoring over packet switched communication networks. In the previous work, we dealt with a simplify situation where the time-varying was in the communication channel from master to the slave. However, we did not implement and test the system with a more complex scenario in which the delay was in both communication paths. The paper presents a complete bilateral teleoperation control scheme to compensate nonlinearity introduced by an Internet like communication channel. The system implements intelligent strategies to maintain the system passivity while it deals with position drift compensation, packets loss and blackouts management. Experimental results using the proposed control scheme are shown.

A Haptic-Assisted Guidance System for working machines based on virtual force fields

This paper presents a new approach to improve the remote navigation of a teleoperated demolition machine. To improve navigation usability of the teleoperated system the following topics will be covered: obstacle avoidance, wall alignment, and machine optimal positioning for demolition operations. In order to enhance the ability of the operator to navigate in a cluttered environment, a Haptic-Assisted Guidance System(HAGS) will be introduced. HAGS is a guidance system based on haptic simulation which improves the awareness of the operator on the surrounding environment. The solution proposed has been tested using a virtual environment scenario and a commercial Haptic interface, the results have been analyzed and discussed.