A control system is provided for automatically moving a machine along a desired path. The machine uses a “learn and follow” system in which the machine is first operated in a manual mode along a desired path. The control system learns the desired path and then operates the machine in a robotic mode to follow the desired path without operator control. If the machine moves away from the desired path when in the robotic mode, the location of the machine is corrected using GPS location signals.

Robotic Vehicle Controller

In many construction and infrastructure management projects, it is important to ensure the flatness of concrete surfaces. Inspectors assess the quality of flat surface construction by checking whether a surface deviates from perfectly flat by more than a specified tolerance. Current flatness assessment methods, such as using a straightedge or shape profiler, are limited in the speed or density of their measurements. Laser scanners are general-purpose instruments for densely and accurately measuring three-dimensional shapes. In this paper, we show how laser scanners can be effectively used to assess surface flatness. Specifically, we formalize, implement, and validate three algorithms for processing laser-scanned data to detect surface flatness deviations. Since different scanners and algorithms can perform differently, we define an evaluation framework for objectively evaluating the performance of different algorithms and scanners. Using this framework, we analyze and compare the performance of the three algorithms using data from three laser scanners. The results show that it is possible to detect surface flatness defects as small as 3 cm across and 1 mm thick from a distance of 20 m.

Characterization of laser scanners and algorithms for detecting flatness defects on concrete surfaces

A wheeled screeding device includes a wheeled support having a frame portion supported by at least one wheel, with the at least one wheel defining an axis of rotation. A screed head is mounted to the frame portion and is balanced such that the screed head is at least partially supportable on an uncured concrete surface. The screed head is adapted to impart a force onto the uncured concrete surface. An adjustment device may be operable to adjust a balance of the wheeled support about the axis of rotation to adjust the force imparted by the screed head. The screed head may be pivotable about an axis generally normal to the axis of rotation of the wheel and relative to the at least one wheel to adjust an angle of the screed head relative to the axis of rotation of the wheel.

Apparatus for screeding uncured concrete surfaces

An electronic device including a processor, a display screen in communication with the processor, a track pad in communication with the processor including a movable surface that is selectively movable in at least one direction to provide feedback to a user, and a feedback system in communication with the processor including a feedback sensor. The feedback sensor determines a movement characteristic of the movable surface and the processor selectively adjusts at least one setting of the track pad based on the movement characteristic.

Feedback systems for input devices

A haptic electromagnetic actuator for track pad is provided. The actuator includes an array of electromagnets with alternating South and North poles on a first end, each magnet comprising a metal core and an electrical wire around the metal core. The array of magnets is coupled to a base plate on a second end opposite to the first end. The actuator also includes an attraction plate at a distance from the first end of the array of the magnets such that the attraction plate moves toward the magnets when an electrical current flows through the electrical wire around the metal core and moves away from the magnets when the current becomes zero. The array of magnets is configured to form a uniform gap from the attraction plate.

Haptic electromagnetic actuator

A lightweight screeding apparatus for screeding and smoothing an uncured concrete surface includes a concrete surface working member, such as vibrating beam or member, and a grade setting device adjustably mounted to said vibrating beam. The screeding apparatus may include a wheeled support which at least partially supports the vibrating beam and/or the grade setting device. The wheels of the wheeled support may be powered or driven to assist an operator in moving the screeding apparatus over and through the uncured concrete. The grade setting device is vertically adjustable to set or indicate the desired grade of the concrete surface as the screeding apparatus is moved over and through the uncured concrete. The grade setting device may be adjusted by means of a laser plane responsive control system.

Lightweight apparatus for screeding and vibrating uncured concrete surfaces

A wheeled strike-off apparatus (10) is movable over a surface of uncured concrete or subgrade materials and is operable to establish a desired grade of the uncured concrete surface or subgrade surface. The apparatus includes a wheeled support (12) and a plow assembly (14). The wheeled support may have a front frame portion (212a) and a pair of front wheels (224) rotatably mounted at the front frame portion, and may have a rear frame portion (212b) and a pair of rear wheels (226) rotatably mounted at the rear frame portion. The plow assembly may be adjustably mounted to the front frame portion and may be vertically adjustable relative to the frame portion via an actuator (230). The plow assembly includes at least one plow member (218) for engaging and establishing the desired grade.

Powered strike-off plow

A soft landing control system (10) for a screeding device (12) is operable to automatically lower a vibrating member (24) of a screed head assembly (14) into engagement with a concrete surface at a time and place where the vibrating member is not positioned over an overlap area of already screeded concrete. The vibrating member is automatically lowered onto newly placed concrete at or near the junction or cold-joint between the already screeded concrete and the area of newly placed concrete, so as to avoid depressions in the already placed concrete. Optionally, the soft landing control system may include a timing device and may lower the vibrating member after a period of time following an activating event. Optionally, the control system may detect when the vibrating device is positioned at or near the newly placed concrete and may lower the vibrating member in response to such detection.

Apparatus and method for improving the control of a concrete screed head assembly

A concrete placing apparatus is provided for placing uncured concrete on a support surface, such as an elevated deck of a building. The apparatus comprises a base unit (16) and a movable support (18), with a conduit assembly (14) extending therebetween. A supply end of the conduit assembly is positioned at the base unit and is connected to a supply line (20) for uncured concrete or other material, while a dispensing end (14c) of the conduit assembly is supported by the movable support and extends outwardly therefrom to dispense uncured concrete or other material through a discharge outlet. The movable support is movable arcuately and/or radially relative to the base unit to dispense the concrete in a generally uniform manner over a targeted area. The apparatus may further include a screeding device (72) at the discharge outlet to grade, level, compact and smooth the concrete as it is placed.

Mark A. Pietila

Papers

Apparatus for screeding uncured concrete surfaces

Lightweight apparatus for screeding and vibrating uncured concrete surfaces

Powered strike-off plow

Apparatus and method for improving the control of a concrete screed head assembly

Concrete placing and screeding apparatus and method